;  BERKELEY 
J 
JNIVWS1TY  OF 
CALIFORNIA 

IARTH 


ELEMENTS 


OF 


E    0    L    0    G    Y 


BY   ALONZO 


AUTHOR    OF 

"ELEMENTS  OF  CHEMISTRY"  AND  "ELEMENTS   OF  NATURAL  PHILOSOPHY," 
AND 


C.  B.  ADAMS,  A.M., 


FELLOW  OF  THE  AMERICAN  ACADEMY  OF  ARTS  AND  SCIENCES,  PROFESSOR  IN 
AMHERST  COLLEGE,  AND  STATE  GEOLOGIST  OF  VERMONT. 


NEW    YORK: 
HARPER    <fe    BROTHERS     PUBLISHERS, 

FRANKLIN     SQUARE 

I860. 


EARTH 

SCIENCES' 

LIBRARY 


Entered,  according  to  Act  of  Congress,  in  the  year  one  thousand 
eight  hundred  and  fifty-two,  by 

HARPER  &  BROTHERS, 

In  the  Clerk's  Office  of  the  District  Court  of  the  Southern  District 
of  New  York. 


772.0 


PREFACE. 


THE  work  now  offered  to  the  public  has  been  prepared 
with  the  design  of  presenting  in  a  condensed  form  the  out 
lines  of  American  and  European  Geology. 

The  recent  geological  surveys  have  made  us  acquainted 
with  the  Geology  of  the  American  continent,  especially  of 
the  United  States  and  the  British  Provinces.  From  the  greai 
amount  of  material  thus  furnished,  such  selections  and  clas- 
sifications have  been  made  as  to  present  American  Geology 
in  a  systematic  form ;  the  subject  is  not  treated,  however, 
with  exclusive  reference  to  America,  but  the  facts  and  de- 
ductions pertaining  to  each  portion  of  the  globe  have  been 
combined  in  one  comprehensive  system. 

Although  the  book  is  elementary  in  its  character,  and  par 
ticularly  designed  for  students  in  Geology,  it  is  not  limited 
to  the  mere  detail  of  facts  or  to  scientific  description ;  but, 
with  a  view  of  rendering  the  subject  attractive  to  the  gen- 
eral reader,  the  most  important  theories  of  the  science  are 
discussed,  with  its  practical  applications  and  relations  to  Nat- 
ural Theology  and  Revelation. 

The  printed  sheets  were  first  used  in  the  instruction  of 
classes  in  Geology,  and  subjected  to  the  criticism  of  scien- 
tific friends.  The  work  has  since  been  revised  and  reprint- 
ed. It  is  believed,  therefore,  that  the  student  will  find  it 
clear  in  statement,  and  free  from  any  important  scientific 
errors. 

Illustrations  for  the  work  have  been  drawn  from  the  whole 


IV  PREFACE.     , 

field  of  geological  phenomena.  Many  of  the  cuts  illustra. 
ting  American  Greology  are  from  original  drawings ;  others 
have  been  taken  from  scientific  journals  and  geological  re- 
ports. The  illustrations  of  European  G-eology  have  been  se- 
lected 'from  standard  works.  The  wood-cuts,  therefore,  may 
be  received  as  faithful  representations  of  the  actu  J  phenom- 
ena which  the  crust  of  the  earth  presents. 

The  table  of  contents  contains  a  complete  analysis  of  each 
subject.  Questions  are  added  at  the  foot  of  each  page,  for 
the  convenience  of  those  who  may  use  the  work  for  element- 
ary instruction. 

Those  portions  of  the  work  from  the  beginning  to  the  ter- 
tiary, and  from  the  triassic  to  the  unstratified  rocks,  were 
first  composed  by  Professor  Adams,  and  the  remainder  by 
Professor  Gray. 

New  York,  October,  1852. 


CONTENTS. 


INTRODUCTION.  Pag 

I.  Object  of  Geology 1 

II.  Relations  of  Geology  to  other  Sciences 2 

III.  Relations  of  Geology  to  the  Arts 3 

IV.  History  of  Geology 4 

CONSTITUTION  OF  THE  EARTH. 

1.  Chemical  Constitution  of  the  Earth 7 

II.  Mineral  Constitution  of  the  Earth 10 

III.  General  Structure  of  the  Earth..                                                   .  12 


PART  I.— GEOLOGICAL  AGENCIES. 

Classification  of  Geological  Agencies 16 

Intensity  of  Geological  Agencies , ib 

CHAPTER  I. — AQUEOUS  AGENCIES. 
Section  1. — Aqueous  Agencies  not  Marine. 

i.  Atmospheric  Agencies 17 

1   Rain,  17;  2  Frost,  18. 

II.  Rivers 19 

III    Bursting  of  Lakes. ., 26 

IV.  Springs .  27 

V    Landslides ~ 28 

VI.  Glaciers „  29 

1.  Origin,  29 ;  2.  Motion,  31 ;  3.  Effects,  33. 
VII.  Avalanches - 35 

Section  2. — Marine  Agencies. 
L  Icebergs ...„.._  36 

1.  Origin,  36 ;  2.  Motion,  38 ;  3.  Dissolution,  40  :  4  Effects,  1.0 
II.  Waves , . 40 

1.  Size,  40 ;  2.  Motion,  41  ;  3.  Effects,  ib 
III.  Oceanic  Currents..  ..... — _  45 


VI  CONTENTS. 

Section  3. — General  Results  of  Aqueous  Agencies.  pHa 

I.  Degradation 46 

a.  Salt  Lakes 47 

III.  Basin-shaped  Deposits ib. 

IV.  Formations  of  Marine  Origin t£. 

CHAPTER  II. — IGNEOUS  AGENCIES. 
Section  1. — Subaerial  Igneous  Agency. 
I.  Volcanoes 5C 

1.  Eruptions,  50 ;  2.  History  of  Vesuvius,  51 ;  3.  History  of 
^Etna,  52 ;  4.  Volcanoes  of  Iceland,  54 ;  5.  Volcano  of  Ki- 
lauea,  55 ;  6.  Volcano  of  Tomboro,  58 ;  7.  Statis  Pressure  in 
Volcanoes,  59  ;  8.  Characters  of  Lava,  ib. 

II.  Earthquakes 60 

1.  Earthquake  of  Lisbon,  60 ;  2.  Earthquakes  in  the  West  In- 
dies, 61 ;  3.  Motion  of  Earthquakes,  ib. ;  4.  Subsidence  and 
Elevation,  62. 
III.  Thermal  Springs 62 

Section  2. — Submarine  Igneous  Agencies. 

I.  Volcanic  Islands 64 

II.  Submarine  Earthquakes 65 

Section  3. — Subterranean  Igneous  Agencies. 

I.  Theory  of  Geysers 66 

II.  Theory  of  Volcanoes ib 

1.  Statement  of  the  Theory  and  Objection,  66 ;  2.  Geographical 
Distribution  of  Volcanoes,  67  ;  3.  Quantity  of  Matter  erupted, 
ib. ;  4.  Alternate  Action,  68. 
III.  Theory  of  Internal  Heat 70 

Section  4. — General  Results  of  Igneous  Agency 72 

CHAPTER  III. — JOINT  EFFECTS  OF  AQUEOUS  AND  IGNEOUS  AGENCIES 74 

CHAPTER  IV. — INORGANIC  AGENCIES  NEITHER  AQUEOUS  NOR  IGNEOUS.,  ib 

CHAPTER  V. — ORGANIC  AGENCIES. 
Section  1. — Corals. 

I.  The  Animals 75 

II.  Temperature  in  which  they  Flourish 76 

III.  Different  kinds  of  Reefs ib. 

1.  Fringing  Reefs,  76 ;  2.  Barrier  Reefs,  ib. ;  3.  Lagoon  Reefs,  77. 

IV.  Extent  of  Coral  Reefs 77 

V.  Rate  of  Increase . .  .78 


CONTENTS.  ViJ 

Pag- 
Section  2. — Animalcules 79 

Section  3.— Shells 80 

Section  4. — Plants  ..  ,     ib 


PART  II.— PRINCIPLES  OF  PALAEONTOLOGY. 
CHAPTER  I. — PRINCIPLES  OP  ZOOLOGY  WHICH  RELATE  TO  FOSSILS. 

Section  1 . — Classification  of  the  Animal  Kingdom 83 

I.  Vertebrata 83 

II.  Articulata ib. 

III.  Mollusca ib. 

Table  of  Classes  of  the  Animal  Kingdom 84 

IV.  Nematoneura 85 

V.  Acrita 86 

Section  2. — Origin  and  Nature  of  Species. 

I.  When  are  Species  introduced ib. 

II.  How  are  Species  introduced 87 

1.  Theory  of  Direct  Creation,  87  ;  2.  Theory  of  Transmutation, 
ib. ;  3.  Theory  of  Equivocal  Generation,  88 ;  4.  Plurality  of 
Origin,  89. 

III.  Nature  of  Species 89 

Section  3. — Duration  of  Species. 

I.  Means  of  their  Preservation 90 

II.  Causes  of  extreme  Longevity ib. 

III.  Comparative  Longevity  of  different  Classes 91 

Section  4. — Extinction  of  Species 92 

Section  5. — Geographical  Distribution 94 

I.  Places  of  Original  Creation 95 

II.  Connection  between  Climate  and  Distribution » ib. 

III.  Connection  between  Station  and  Distribution 96 

Section  6. — Determination  of  Organic  Remains 98 

I.  By  the  necessary  Relations  of  Parts 99 

II.  By  other  invariable  Relations 100 

CHAPTER  II. — FOSSILIZATION. 

Section  1 . — Durability  of  Organic  Bodies ..... . ib 

I,  Of  Vertebrated  Animals <L 101 

II    Of  Articulated  Animals 103 

III    Of  Molluscous  Animals..                                                              .  104 


Vlll  CONTENTS. 

Fi;. 

IV.  Of  the  Nematoneura 104 

V.  Of  the  Acrita , ib. 

Section  2. — Burial  of  Organic  Bodies 105 

I.  Human  Agency ib. 

II.  Natural  Agencies 106 

Section  3. — Modes  and  Degrees  of  Preservation. 

I.  Petrifaction 108 

II.  Molds  and  Casts ib. 

III.  Preservation  without  Change 109 

IV.  Incrustation ib. 

Section  4. — Comparison  of  the  Number  of  Fossil  and  Living  Species.,  ib 


PART  III.— HISTORY  OF  THE  EARTH. 

CHAPTER  I. — SOURCES  OF  KNOWLEDGE. 
Section  1. — Relative  Age  of  the  Stratified  Rocks — how  ascertained. 

I.  By  the  position  of  the  Strata Hi 

II.  By  the  Fossils llfc 

III.  By  Conglomerates ib. 

IV.  By  Comparison  of  the  Fossils  with  existing  Species ib. 

V.  By  their  Lithological  Characters 113 

VI.  By  their  Mineral  Contents 114 

Section  2. — Relative  Age  of  the  Unstratified  Rocks ib 

Section  3. — History  of  each  Period — how  learned ib 

CHAPTER  II. — MEANS  OF  OBSERVATION. 

Section  1. — Artificial  Excavations 115 

Section  2. — Natural  Means 116 

I.  River  Courses  and  Lines  of  Sea-coast ib. 

II.  Uplifts ib. 

III.  Inclination  of  the  Strata 117 

CHAPTER  III. — CLASSIFICATION  OF  THE  STRATIFIED  ROCKS. 
Section  1. — Classes  of  Strata. 

I.  Primary  Strata 118 

II.  Palaeozoic  Rocks ib. 

III.  Mesozoic  Rocks  or  Secondary  Strata 119 

IV.  Tertiary  Strata ib 

V.  Quaternary  Strata ib 

Section  2. — Tabular  View  of  the  Formations 120 


CONTENTS.  IX 

CHAPTER  IV. — QUATERNARY  SYSTEM  Paga 

Section  1. — Drift 123 

I    Lithological  Characters  of  Drift il. 

II.  Geographical  Limits  of  Drift 1*24 

/II    Transport  of  Drift ib. 

1.  Vertical  Distribution,  124 ;  2.  Direction  of  Transport,  125  ; 
3.  Distance  of  Transport,  ib. ;  4.  Correspondence  between 
durability  and  abundance  of  Bowlders,  ib. ;  5.  Obstructions 
to  Transport,  126;  6.  Size  of  Bowlders,  127. 

IV.  Wearing  down  of  Solid  Rocks 12? 

1.  Characters  of  the  Striae,  Furrows,  &c.,  127;  2.  Univer- 
sality of  the  Phenomena,  130 ;  3.  Greatest  Height  and 
lowest  Level  of  Striated  Rocks,  ib. ;  4.  Effect  of  Obstruc- 
tions, ib. ;  5.  Stoss  and  Lee  Sides,  131 ;  6.  Different  Sets 
of  Striae,  132 ;  7.  Striae  of  European  Drift,  ib. ;  8.  Syn- 
chronism of  these  Phenomena  and  the  Transport  of  Drift, 
133. 

7.  Streams  of  Stones 133 

1.  General  Characters  and  Age,  133 ;  2.  Example  in  Hunt- 
ington,  Vermont,  134. 

VI.  Age  of  the  Drift 135 

1.  Of  North  American  Drift,  135  ;  2.  Of  European  Drift,  ib. 
VII.  Theories  of  Drift 136 

1.  Iceberg  Theory,  136;  2.  Theory  of  Elevations,  137;  3. 
Glacier  Theory,  138. 

nil.  Fracture  of  Slate  Hills 140 

Section  2. — Pleistocene. 
I.  Lithological  Characters 141 

1.  Origin  of  the  Materials,  141 ;  Of  the  Beds  of  Clay  and  Sand; 
Of  altered  Drift,  142  ;  Hillocks  of  altered  Drift,  143  ;  CEsars, 
144  ;  2.  Interstratification  of  the  Materials,  145 ;  3.  River 
Terraces,  ib. ;  4.  Marine  Terraces,  147. 

II.  Topography 147 

III.  Organic  Remains 148 

1.  In  North  America — Marine  Shells,  148  ;  Fresh-water  Shells ; 
Mammalia,  149 ;  Mastodon,  150 ;  Elephant ;  Whale,  151 ; 

2.  In  South  America — Shells  ;  Mammalia ;  Mylodon,  153  ; 
Megatherium,  154;   3.  In  Europe — Mammalia,  156;  4.  In 
New  Zealand — Birds,  ib. ;  5.  In  Siberia,  Mammoth,  ib. 

IV    Age  of  the  Pleistocene  Period 1 58 

Relation  to  the  Drift,  158  ;  Relation  to  the  Historical  Period ; 
Synchronism  of  different  Deposits ;  Length  of  the  Period,  159. 
A2 


CONTENTS, 

Pa*« 

V.  Geography  of  the  Pleistocene  Period 160 

Sources  of  Knowledge ;  Sea  Levels  in  New  England,  160  ; 
Effects  of  the  Submergence ;  Sea  Levels  in  the  Southern 
States  ;  Submergence  in  South  America,  161 ;  Sea  Levels 
in  Scandinavia ;  Submergence  in  Asia ;  Probable  extent  of 
Land  in  Polynesia,  162. 
VI.  Climate  of  the  Pleistocene  Period 163 

In  North  America,  163  In  Europe ;  In  Siberia  •  In  South 
America,  164. 

CHAPTER  V. — TERTIARY  PERIOD. 

1.  Geographical  Distribution,  164;  2.  Composition  and  Struc 
ture,  165 ;  3.  Classification,  ib. 

Section  I . — Pliocene  or  Newer  Tertiary. 

I.  Pliocene  of  the  United  States l($r 

1.  Geographical  Distribution,  166 ;  2.  Composition,  ib. ;  3. 
Geological  Position,  ib. 

II.  European  Pliocene 16' 

1.  Norwich  Crag,  167;  2.  Val  di  Noto,  ib. ;  3.  Sub-Apennine 
Tertiary  Beds,  169 ;  4.  Brown  Coal  Formation,  ib. ;  5,  La- 
custrine fresh- water  Formation  of  the  Rhine,  170. 

III.  Fossils  of  the  Pliocene 170 

1.  Vegetables,  170 ;  2.  Animals,  ib.. 

Section  2. — Miocene  or  Middle  Tertiary. 

I.  Miocene  of  the  United  States 172 

1.  Gayhead,  173 ;  2.  Maryland,  Virginia,  ib. ;  3.  General  De- 
scription of  American  Miocene,  175. 

[I.  European  Miocene 177 

1.  Coralline  Crag,  177 ;  2.  Basin  of  the  Garonne,  178  ;  3.  Valley 
of  Switzerland,  ib. ;  4.  Basins  of  Vienna  and  Styria,  179 ;  5. 
Miocene  Basins  of  Auvergne  (fresh-water),  180. 

J1I.  Fossils  of  the  Miocene  .. 181 

1.  Vegetables,  181 ;  2.  Animals,  ib. 

Section  3. — Eocene  or  Older  Tertiary. 

I.  Geographical  Distribution / 187 

II.  Eocene  of  the  United  States 18" 

1.  Buhr-stone  Formation  (South  Carolina),  187;  2.  Santee 
Beds,  188;  3.  Ashley  and  Cooper  Rivers,  ib. ;  4.  James 
River  (Virginia),  ib. ;  5.  Eocene  of  the  Southern  States,  189; 
3.  Tabular  View  of  the  Eocene  of  the  United  States,  ib. 


CONTENTS.  XI 

Pago 

HI.  European  Eocene 189 

1.  Basin  of  the  Thames,  190;  2.  Hampshire  Basin,  191;  3. 
Paris  Basin,  ib. ;  4.  Eocene  Basins  of  Auvergne,  193 ;  5. 
Nummulitic  Formation  of  the  Alps,  195. 
IV.  Fossils  of  the  Eocene 195 

1.  Vegetables,  196 ;  2.  Animals,  197. 

Section  4. — Climate  and  Physical  Geography  of  the  Tertiary. 
1.  Climate,  206 ;  2.  Physical  Geography,  ib. 

CHAPTER  VI. — SECONDARY  PERIODS. 
Section  1. — Cretaceous  System. 

I.  European  Cretaceous  Series 211 

1.  Upper  Chalk,  212 ;  2.  Middle  and  Lower  Chalk,  ib. ;  3.  Chalk 
Marl,  ib. ;  4.  Upper  Green  Sand,  213 ;  5.  Gault,  ib. ;  6.  Lowei 
Green  Sand,  ib. 

fl.  American  Cretaceous  System 214 

Distribution ;  Character  of  the  Strata,  Composition,  &c.,  214. 

Ill-  Fossils  of  the  Cretaceous  System 215 

1.  Vegetables,  215;  2.  Animals,  216. 

Section  2. — Wealden  Formation. 

I.  Composition 222 

1.  Weald  Clay,  222  ;  2.  Hastings  Sand,  ib.;  3.  Purbeck  Strata, 

223. 
n.  Fossils  of  the  Wealden 224 

1.  Vegetables,  224 ;  2.  Animals,  ib. 

Section  3. — Oolitic  System. 

I.  Oolite  of  the  United  States 226 

IT.  European  Oolite 227 

1.  Upper  Oolites,  227 ;    2.  Middle  Oolites,  228 ;    3.  Lower 

Oolites,  229  ;  4.  Oolites  of  the  Jura,  230. 
III.  Fossils  of  the  Oolite 231 

Vegetables ;  Animals,  231. 

Section  4. — Liassic  System. 
I.  Subdivisions 235 

1.  Upper  Lias,  235  ;  2.  Middle  Lias,  236  ;  3,  4.  Lower  Lias,  ib. 

II.  Fossils  of  the  Lias 236 

1.  Plants,  236;  2.  Animals,  ib. 

Section  5. — Triassic  or  New  Red  Sandstone  System. 
I.  Geographical  Distribution 241 

II.  Composition  and  Structure ib. 


H  CONTENTS. 

Pa«» 

III.  Trias  of  North  America 241 

IV.  European  Trias 242 

V.  Fossils  of  the  Trias 243 

1.  Plants,  243;  2.  Radiated  Animals,  ib. ;  3.  Mollusca,  244;  4. 
Articulata,  ib. ;  5.  Fishes,  ib. ;  6.  Reptiles,  245 ;  Birds  and 
Batrachians,  245-252. 

CHAPTER  VII. — PALAEOZOIC  PERIODS. 
Section  1. — Permean  System. 

1.  Geographical  Distribution 254 

II.  Structure  and  Position ib 

III.  Fossil  Plants ib. 

IV.  Fossil  Animals ib. 

1.  Radiata,  255;  2.  Mollusca,  ib. ;  3.  Articulata,  ib.;  4.  Fishes, 
256  ;  5.  Reptiles,  ib. 

Section  2. — Carboniferous  System. 

I.  Geographical  Distribution 256 

II.  Structure  and  Position 257 

III.  Fossils 259 

1.  Plants,  259;  (1.)  Calamites,  ib.;  (2.)  Ferns,  260;  (3.)  Lepi- 
dodendron,  261 ;  (4.)  Sigillaria  and  Stigmaria,  262 ;  2.  Ani- 
mals, 265;  (1.)  Radiated  Animals,  ib. ;  (2.)  Molluscs,  266; 
(3.)  Fishes,  268  ;  (4.)  Reptiles,  ib. 

IV.  Climate  and  Geography 269 

Section  3. — Devonian  System— Old  Red  Sandstone. 

I.  Geographical  Distribution 27U 

II.  Structure  and  Position 271 

HI.  Fossils ib. 

1.  Plants,  271 ;  2.  Animals,  ib. ;  (1.)  Radiata,  ib.;  (2.)  Articu- 
lata, ib. ;  (3.)  Molluscs,  272  ;  (4.)  Fishes,  ib. 

Section  4. — Silurian  System. 

I.  Geographical  Distribution 274 

II.  Structure  and  Position ib. 

III.  Subdivisions  of  Silurian  System 276 

ry.  Fossils 277 

1.  Radiata,  277;  (1.)  Corals,  ib. ;  (2.)  Graptolites,  279;  (3.) 
Crinoideans,  ib. ;  2.  Articulata,  280  ;  3.  Mollusca,  ib.  ,•  4. 
Fishes,  283  ;  5.  Plants,  ib. 

V.  Climate  and  Geography 283 

Cumbrian  and  Cambrian  Series ib. 

Taconic  Rocks .  284 


CONTENTS.  Xlll 

CHAPTER  VIII. — METAMORPHIC  AND  PRIMARY  STRATA  Tf^ 

Clay   Slate;    Crystalline  Marble,   288;    Hornblende   Slate- 
Quartz  Rock ;  Mica  Slate  ;  Gneiss,  289. 

CHAPTER  IX. — UNSTRATIFIED  ROCKS. 
Section  1. — Granitic  Rocks. 

I.  Granite 291 

1.  Varieties  of  Granite,  292 ;  2.  Porphyritic  Granite,  ib. ;  3. 

Talcose  Granite,  ib. ;  4.  Feldspathic  Granite,  ib. 
II.  Syenite 292 

III.  Quartz  Rock 293 

IV.  Geographical  Distribution  of  Granitic  Rocks ib. 

V.  Geological  Position  and  Age 294 

Section  2. — Trappean  Rocks. 

I.  Porphyry 295 

II.  Greenstone ib. 

III.  Trachyte : ib. 

IV.  Basalt - ib. 

V.  Amygdaloid 296 

VI.  Columnar  Structure ib. 

VII.  Geographical  Distribution 297 

VIII.  Geological  Position  of  the  Trap  Rocks 299 

Section  3. — Volcanic  Rocks. 
1.  Trachytic  Lava,  300  ;  2.  Basaltic  Lava,  ib. ;  3.  Graystone 

and  Pitchstone  Lavas,  ib. 
Extinct  Volcanoes  .... 300 

Section  4. — Origin  of  the  Unstratified  Rocks. 

I.  Structure  and  Composition 301 

II.  Position ib. 

TIL  Mechanical  and  Chemical  Effects 302 

Section  5. — Origin  of  the  Stratified  Rocks 303 

Section  6. — Nebular  Hypothesis 304 

CHAPTER  X. — ANTIQUITY  OF  THE  EARTH. 

Section  1. — Antiquity  of  the  Earth,  as  inferred  from  the  Structure,  Composition, 
and  Position  of  the  Rocks. 

I.  Basis  of  the  Argument 307 

II.  Character  and  Position  of  the  Strata ib. 

III.  Relation  of  the  Unstratified  to  the  Stratified  Rocks..  ..  309 


XIV  CONTENTS. 

Section  2. — Antiquity  of  the  Earth,  as  inferred  from  the  Remains  of  Organize* 

Beings.  pagt 

I.  Distribution  and  Abundance  of  Fossils 310 

II.  Specific  Examples  of  Fossil  Plants 312 

1.  Peculiar  Character  of  the  Coal  Plants,  312 ;  2.  Character 
and  Position  of  the  Coal  Beds,  and  Extent  of  Coal-fields,  ib. 
III.  Examples  of  Fossil  Animals 316 

Section  3. — Antiquity  of  the  Earth,  as  inferred  from  the  Mutual  Relations  of  the 

Organic  and  Inorganic  Portions  of  the  Earth's  Crust. 
I.  Examples  from  the  Tertiary  (Auvergne) 317 

II.  Examples  from  the  Tertiary  in  Italy  and  Sicily 318 

III.  Examples  from  Chalk  and  Wealden 319 

IV.  Examples  from  Oolitic  and  other  Groups  below ib. 

V.  River  Terraces 320 

VI.  Coral  Islands ib. 

VII.  Numerical  Estimates  of  the  Age  of  the  World 321 

Section  4. — Objections  to  the  Antiquity  of  the  Earth  considered. 

I.  Hypothesis  of  the  Noachian  Deluge 323 

1.  Objections  to  this  Hypothesis  derived  from  Fossil  Trees,  323 ; 

2.  Objections  to  this  Hypothesis  derived  from  Animals,  ib. ; 

3.  Objections  to  this  Hypothesis  derived  from  Rocks,  ib.;  4. 
Conclusions  on  the  supposition  that  this  Hypothesis  is  True, 
324. 

II.  Hypothesis  of  a  Change  of  the  Laws  of  Nature  after  the  Fall  of 

our  First  Parents 325 

III.  Hypothesis  which  ascribes  all  the  Phenomena  of  the  Crust  of  the 

Earth  to  the  direct  Power  of  God ib. 

CHAPTER    XI. — CONNECTION   OP   GEOLOGY  WITH  NATURAL   THEOLOGY  AND 

WITH  REVELATION. 
Section  1. — Geology  and  Natural  Theology. 

I.  Infinite  Power  of  God 330 

II.  Intelligence  and  Wisdom 331 

III.  Unity  of  God ib. 

IV.  Benevolence  of  God 332 

V.  Extent  of  the  Plans  of  God 334 

Section  2. — Connection  of  Geology  with  Revelation. 
I.  Apparent  Discrepancy  between  Geology  and  Revelation  in  re. 

spect  to  the  Age  of  the  World 338 


CONTENTS.  XV 

Pap 

I.  Meaning  of  the  phrase  "In  the  beginning,"  336;  2.  The 
first  verse  of  the  first;  chapter  of  Genesis  susceptible  of  two 
Interpretations — Tru3  Interpretation  settled,  337;  (1.)  Ob- 
ject of  a  Revelation,  ib. ;  (2.)  Character  of  the  People  to 
whom  the  Revelation  was  given,  338 ;  (3.)  The  Facts  of 
Science  may  be  used  to  decide  the  Question,  339  ;  3.  This 
Interpretation  consistent  with  the  remaining  portions  of  the 
Chapter,  ib. 
II.  Second  apparent  Discrepancy,  the  Introduction  of  Death  and  the 

Reasons  therefor 346 

1.  Structure  of  Carnivorous  Races,  347;  2.  Death  the  Result 
of  Organization,  ib. ;  3.  Theory  to  Reconcile  the  Existence 
of  Death  previous  to  Sin,  348  ;  Conclusion,  350. 


INTRODUCTION, 


1.  Geology  is  that  Science  which  investigates  the  physical  History 
of  the  Earth. — This  history  is  written  in  the  layers  and  masses  of 
mineral  matter  which  constitute  the  crust  of  the  earth,  and  be- 
comes intelligible  in  the  investigation  of  the  successive  changes 
to  which  the  earth  has  been  subjected. 

In  the  study  of  Geology,  the  first  step  is  to  obtain  a  knowledge 
of  the  forces  which  are  now  active,  in  respect  of  the  manner  in 
which  they  act  and  of  the  effects  which  they  produce.  The  sec- 
ond step  is  the  application  of  the  knowledge  thus  obtained  to  the 
explanation  of  similar  effects  in  the  earth's  crust.  "We  shall  be 
able  to  understand  the  changes  of  which  these  effects  are  the  me- 
morials. If  also,  in  the  third  place,  by  means  to  be  hereafter  ex- 
plained, we  can  ascertain  the  order  of  time  in  which  the  events 
have  occurred,  we  shall  have  a  connected  history. 

It  is  obvious  that  the  basis  of  this  reasoning  is  the  analogy  be- 
tween the  past  and  the  present  laws  of  nature ;  for,  however  the 
circumstances  may  differ,  the  elementary  forces  are  ever  the  same. 
With  perfect  confidence  in  their  uniformity,  the  astronomer  pre- 
dicts a  future  eclipse,  and  the  geologist  describes  extinct  animals 
and  plants. 

Thus  we  may  show  that  there  has  been  a  different  distribution 
of  land  and  water,  and  that  mountains  have  arisen,  in  successive 
periods,  so  as  to  obliterate  all  resemblance  between  this  truly  an- 
cient and  our  modern  Geography.  We  may  also  see  many  suc- 
cessive races  of  the  animal  and  vegetable  inhabitants  of  the  globe, 

Define  Geology.  What  is  the  first  step  in  the  study  of  Geology?  the  sec- 
ond? the  third?  What  is  the  basis  of  geological  reasoning?  What  are  the 
results  ? 

A 


2  INTRODUCTION 

different  from  each  other  and  from  those  which  now  exist,  ap- 
pearing, and  afterward  becoming  extinct  in  an  uninterrupted  se- 
ries, of  which  the  beginning  and  end  are  known  only  to  the  Cre- 
ator. 

II.  Relations  of  Geology  io  other  Sciences. — These  relations  are 
those  of  mutual  dependence. 

1.  The  effects  of  heat  on  mineral  substances,  and  the  action  of 
the  substances  on  each  other,  can  not  be  investigated  without  the 
aid  of  Chemistry.     The  principles  of  Mechanics  are  used  in  the 
investigation  of  the  manner  in  which  the  great  agents,  water  and 
heat,  effect  the  removal  of  materials  and  elevate  mountain  chains, 
and  in  which  the  glaciers  of  the  present  and  of  a  former  period 
have  modified  the  surface  of  countries.     The  magnetic  influences 
which  pervade  the  earth's  crust  ally  Geology  with  another  branch 
of  science. 

Without  Botany  and  Zoology,  the  geologist  could  not  interpret 
the  wonderful  records  which  are  preserved  in  the  form  of  fossil 
remains.  These  sciences  enable  him  to  perceive  that  most  of 
the  fossils  belong  to  extinct  species.  They  also  enable  him  to  un- 
derstand the  habits  of  these  species,  and  their  relations  to  each 
other,  and  to  the  varying  condition  of  the  earth's  surface.  Com- 
parative anatomy  aids  in  showing  how,  from  a  fragment,  to  re- 
construct the  whole  animal. 

On  Mineralogy  Geology  depends  for  a  knowledge  of  the  visi- 
ble composition  of  rocks.  A  knowledge  of  their  mineral  consti- 
tution often  enables  the  geologist  to  understand  their  origin  and 
history. 

2.  In  return  for  these  favors,  Geology  directs  to  the  localities 
of  useful  minerals,  and  throws  much  light  on  their  origin.     It  re- 
stores many  species  of  organic  bodies  which  have  been  buried  in 
the  earth,  and  enables  the  naturalist  to  fill  up  many  wide  gaps 
in  the  plan  of  the  existing  creation.     It  also  carries  back  the 

Of  what  nature  are  the  relations  of  Geology  to  other  sciences  ?  What  aid 
does  it  derive  from  Chemistry  and  Mechanics  ?  What  from  Botany  and  Zo 
ology?  What  from  Mineralogy?  What  aid  do  other  sciences  derive  from 
Geology? 


INTRODUCTION.  3 

history  of  the  animal  and  vegetable  kingdc  ms  into  inconceivably 
remote  periods,  and  exhibits  the  plan  of  creation  as  extending 
throughout  time.  It  throws  much  light  on  questions  relating  to 
the  origin,  the  nature,  and  the  destiny  of  species.  The  present 
distribution  of  animals  and  plants  over  the  surface  of  the  earth 
is  much  influenced  by  the  nature  of  the  geological  formations. 

The  more  intimate,  therefore,  the  acquaintance  of  the  geolo- 
gist with  these  kindred  sciences,  the  more  successful  and  accu- 
rate will  be  his  investigations.  It  is  not  essential,  however,  that 
his  knowledge  of  them  should  embrace  much  more  than  the  gen- 
eral results  of  the  labors  of  others  who  are  specially  devoted  to 
them.  Still  more  ordinary  attainments  will  suffice  for  the  pur 
poses  of  the  general  reader  of  Geology. 

III.  Relations  of  Geology  to  the  Arts. — The  economical  rela- 
tions of  Geology  may  be  chiefly  comprehended  under  the  general 
divisions  of  agriculture,  mining,  architecture,  and  engineering. 

1.  For  the  agriculturist,  it  detects  beds  of  marl  and  peat,  of 
limestone,  of  green  sand,  of  phosphate  of  lime,  and  of  gypsum. 
It  also  enables  him  to  understand  the  origin  of  his  soils. 

2.  For  the  miner,  it  often  decides,  on  a  moment's  inspection, 
whether  certain  minerals  may  occur  or  can  not  occur  in  a  given 
region ;  for  many  valuable  substances  are  found  only  in  a  very 
limited  part  of  the  geological  series  of  rocks.     It  also  assists  the 
miner  to  understand  the  mode  of  the  occurrence  of  minerals. 
This  may  be  in  layers  more  or  less  parallel  with  the  rocky  strata, 
or  in  veins  cutting  across  them.     They  may  be  in  regular  or  ir 
regular  masses,  or  may  be  merely  a  disseminated  constituent  ol 
a  rock.     A  knowledge  of  these  facts,  and  of  their  causes,  is  usu 
ally  essential  to  success  in  mining. 

3.  To  the  architect  Geology  is  of  great  service  in  the  selection 
of  building  sites,  and  in  the  choice  of  stones,  or  of  materials  for 
bricks. 

4.  The  engineer  also  is  aided  by  Geology  in  choosing  the  besl 
line  in  the  arrangement  of  excavations  and  embankments,  and  in 

What  are  the  relations  of  Geology  to  agriculture  ?  to  mining  ?  to  architect- 
we  ?  to  engineering  ? 


4  INTRODUCTION. 

the  selection  of  the  materials  for  the  construction  of  roads  and 
canals. 

IV.  History  of  Geology. — The  remarks  which  have  been  made 
on  the  connection  between  Geology  and  other  natural  sciences, 
suggest  an  obvious  cause  of  the  recent  origin  of  Geology  properly 
30  called.  The  sciences,  without  whose  interpretation  the  facts 
•  >f  Geology  are  unintelligible,  are  themselves  of  recent  origin. 

Speculations  on  the  process  of  creation,  and  idle  hypotheses 
of  the  phenomena  of  fossils  and  of  the  stratified  and  the  crystal- 
line rocks,  mingled  with  occasional  glimpses  of  true  theories, 
make  up  the  history  of  the  subject  until  the  latter  part  of  the  last 
century.  At  that  time,  Werner,  a  German  professor  in  a  school 
of  mines,  proposed  and  defended  the  Neptunian  theory.  This 
theory  accounted  for  all  the  rocks  by  the  aqueous  deposition  of 
strata,  which  were  supposed  to  be  originally  continuous  over  the 
whole  surface  of  the  earth.  Werner  was  the  father  of  Mineral- 
ogy ;  but  the  title  of  the  father  of  Geology  belongs  to  Hutton,  a 
Scotch  geologist,  who  soon  after  proposed  the  Plutonian  theory. 
According  to  Hutton's  theory,  which  has  been  established,  the 
unstratified  rocks  are  of  igneous  origin,  like  the  lavas  of  the  pres- 
ent epoch,  and  the  stratified  rocks  were  originally  sand,  clay, 
mud,  gravel,  &c.,  like  the  aqueous  deposits  of  the  present  time. 
Hutton  supposed  that  these  deposits  were  derived  from  the  abra- 
sion of  ancient  continents ;  that  some  of  them  were  rendered 
crystalline  by  the  heat  of  protruded  igneous  rocks  ;  and  that  in 
such  a  series  of  changes  Geology  can  discover  no  proof  of  a  be- 
ginning nor  prospect  of  an  end. 

After  much  discussion,  in  which  Werner's  theory  was  abandon 
ed,  geologists  applied  themselves  to  laying  a  durable  foundation 
for  the  science,  in  the  collection  and  systematic  study  of  facts. 
Mr.  William  Smith,  an  English  geologist,  although  in  an  obscure 
position,  was  the  real  pioneer  and  head  of  this  movement.  In 
the  latter  part  of  the  last  and  the  commencement  of  the  present 
century,  he  accomplished  more  for  British  Geology  than  all  his 

Cause  of  the  recent  origin  of  Geology  ?  What  was  the  Neptunian  theory?  the 
Plutonian  theory  ?  What  was  the  subsequent  history  of  European  Geology  ? 


INTRODUCTION.  & 

cotemporaries.  In  1807  the  Geological  Society  of  London  was 
formed,  which  was  followed  by  other  European  societies.  The 
enthusiastic  efforts  of  men  of  wealth  and  of  distinguished  talents, 
with  occasional  aid  from  governments,  in  almost  all  parts  of  Eu- 
rope, have  resulted  in  the  collection  of  a  vast  amount  of  materials. 
These,  with  the  legitimate  deductions,  constitute  a  science  which 
is  now  in  most  of  its  parts  as  well  established  as  Astronomy. 

The  most  prominent  features  in  the  history  of  geological  opii 
ions,  during  the  second  quarter  of  this  century,  have  been  tl  < 
theory  of  internal  heat,  and  the  question  of  a  uniform  or  a  dimin- 
ished intensity  in  the  action  of  geological  agencies. 

The  oldest  book  on  the  geology  of  America  was  a  German 
work  written  by  Dr.  J.  D.  Schopf,  and  published  in  1787.  But 
the  study  of  American  Geology  was  effectually  commenced  in 
1807  by  William  Maclure,  who  alone  explored  a  large  part  of 
the  United  States,  and  published  a  geological  map  of  the  coun- 
try. Mr.  Maclure  was  soon  followed  by  Dr.  Bruce,  Professor 
Silliman,  and  at  length  by  a  numerous  body  of  able  geologists. 

In  1824  was  commenced  a  series  of  geological  surveys  of  most 
of  the  United  States,  made  under  the  authority  of  the  State  Leg- 
islatures. The  following  is  a  chronological  list  of  these  surveys, 
with  the  dates  of  their  commencement : 

1824.  North  Carolina  ;  by  Prof.  Denison  Olmsted. 

1830.  Massachusetts ;      "      "      Edward  Hitchcock. 

1833.  Tennessee;  "      "      G.  Troost. 

1834.  Maryland ;  "      "      J.  T.  Ducatel. 

1835.  New  Jersey  j         "      "      Henry  D.  Rogers. 
1835.  Virginia ;  "      "      Wm.  B.  Rogers. 

1835.  Connecticut;          "    Dr.  J.  G.  Percival  and  Prof.  C.  U. 

Shepard. 

1836.  New  York ;  «    Profs.  W.  W.   Mather,   Lardner 

Vanuxem,  Ebenezer  Emmons 
Mr.  James  Hall,  and  Mr.  Tim 
othy  Conrad. 

Who  were  the  first  cultivators  of  Geology  in  America  ?  What  means  have 
been  employed  to  develop  the  Geclogy  of  the  United  States  ? 


D  INTRODUCTION. 

1836.  Maine ;  by  Dr.  C.  T.  Jackson. 

1836.  Pennsylvania;  "   Prof.  Henry  D.  Rogers. 

1836.  Georgia;  "   John  R.  Cotting,  Esq. 

1837.  Delaware  ;  "   Prof.  James  C.  Booth. 

1837.  Indiana  ;  "   Dr.  David  D.  Owen. 

1838.  Michigan  ;  "   Douglass  Houghton,  Esq. 

1838.  Kentucky ;  a  reconnoissance  only ;  by  Prof.  W.  W.  Ma« 

ther. 

1839.  Ohio;  by  Prof.  W.  W.  Mather. 

1839.  Rhode  Island ;       "   Dr.  C.  T.  Jackson. 

1840.  New  Hampshire;  "  Dr.  C.  T.  Jackson. 

1842.  Louisiana;  a  reconnoissance;  by  Prof.  W.  M.  Carpen- 
ter. 

1844.  Vermont ;  by  Prof.  C.  B.  Adams. 

Geological  surveys  have  been  made,  or  are  in  progress  in  sev- 
eral of  the  territories,  and  in  the  British  provinces. 

These  surveys  have  not  only  accomplished  their  object  of  de- 
veloping the  mineral  wealth  of  the  country,  but  they  have  also  ac- 
cumulated a  great  amount  of  materials  for  science.  It  is  to  be 
regretted,  however,  that  some  of  the  states  have  not  published 
final  reports,  in  which  cases  most  of  the  results  are  likely  to  be 
lost. 

In  1840,  an  association  was  formed  for  the  advancement  of 
Geology,  by  the  gentlemen  who  had  been  engaged  in  the  state 
surveys.  It  soon  comprehended  all  objects  of  Natural  History ; 
and  in  1847  it  was  resolved  into  a  more  general  "American  As- 
sociation for  the  Promotion  of  Science."  This  association  holds 
annual,  and  sometimes  semi-annual,  meetings  in  different  parts  of 
the  country. 

What  was  the  origin  of  the  American  Association  for  the  Promotion  cf  Sci» 
once? 


CONSTITUTION  OF  THE  EARTH. 


I.  Chemical  Constitution  of  the  Earth. — Of  the  sixty-two  sim- 
ple substances  which  are  known  to  chemists  only  sixteen  con- 
stitute the  greater  part  of  the  earth's  crust.  The  other  forty-six 
exist  for  the  most  part  in  rare  minerals,  or  are  disseminated  in 
very  minute  proportion  through  the  more  common  substances. 

1.  Oxygen  is  the  most  abundant  of  all  elementary  substances. 
In  a  free  state  it  constitutes  one  fifth  of  the  atmosphere.     In  com- 
bination it  forms  eight  ninths  of  water,  and  two  fifths  to  one  half 
)f  all  the  solid  materials  of  the  globe.     It  enters  largely  into  the 
composition  of  all  the  earths,  and  of  most  of  the  earthy  minerals 
and  ores  of  the  metals. 

2.  Silicon  permanently  exists  in  nature  only  in  combination 
with  oxygen,  in  nearly  equal  parts,  forming  silica,  which  is  also 
called  silicic  acid.     This  compound  constitutes  forty-five  to  fifty 
per  cent,  of  the  earth's  crust,  one  quarter  of  which  is  therefore 
silicon.     Pure  quartz  is  silica,  and  consequently  silicon  exists  in 
most  of  the  rocks  and  minerals. 

3.  Calcium  exists  chiefly  in  combination  with  oxygen,  forming 
lime,  of  which  it  constitutes  nearly  two  thirds.     The  lime  exists 
mostly  in  combination  with  carbonic  acid,  forming  carbonate  of 
lime.     About  seven  per  cent,  of  the  earth's  crust  is  calcium. 

4.  Aluminium  exists  in  nature  only  in  combination  with  oxy 
gen,  in  nearly  equal  parts,  forming  alumina.     This  compound 
constitutes  one  fifth  of  feldspar,  and  exists  in  most  minerals  and 
rocks.     Probably  about  five  per  cent,  of  the  earth's  crust  is  alu- 
minium. 

5.  Magnesium  exists  in  nature  mostly  in  combination  with  oxy- 

Of  how  many  substances  is  the  crust  of  the  earth  chiefly  composed  ?  What 
is  said  of  oxygen  ?  of  silicon  ?  of  calcium  ?  of  aluminium  ?  of  magnesium  ? 


8  CONSTITUTION    OF    THE    EARTH. 

gen,  forming  magnesia,  of  which  it  constitutes  about  three  fifths. 
Magnesia  forms  about  forty  per  cent,  of  serpentine,  and  ten  to 
twenty  per  cent,  of  dolomite.  Probably  about  three  per  cent,  of 
the  earth's  crust  is  magnesium. 

6.  Iron  is  rarely,  if  ever,  found  native,  except  in  meteoric  stones. 
It  is  mostly  combined  with  oxygen,  frequently  with  sulphur,  and 
sometimes  with  carbon.     It  forms  nearly  two  per  cent,  of  the 
crust  of  the  globe. 

7.  Carbon  exists  mostly  in  combination  with  oxygen,  forming 
carbonic  acid,  in  the  proportion  of  six  parts  of  carbon  and  sixteen 
parts  of  oxygen.     This  gas  constitutes  about  -g^o^h  °f  tne  at> 
mosphere,  but  is  chiefly  locked  up  in  a  solid  state  in  combination 
with  lime,  magnesia,  &c.,  forming  the  carbonates  of  those  bases. 
Carbon  also  exists  in  a  free  state  in  the  various  kinds  of  mineral 
coal.     Nearly  two  per  cent,  of  the  earth's  crust  is  carbon. 

8.  Potassium  exists  in  nature  almost  wholly  in  combination 
with  oxygen,  forming  potassa,  of  which  it  constiiares  about  five 
sixths.     Potassa  exists  chiefly  in  feldspar  and  clay,  in  the  soil,  &c. 
Potassium  forms  nearly  five  per  cent,  of  the  unstratified  rocks, 
being  about  one  tenth  of  the  feldspar  in  them,  arid  constitutes 
about  one  per  cent,  of  the  total  of  the  earth's  crust. 

9.  Hydrogen  resides  chiefly  in  water,  of  which  it  forms  one 
ninth  part.     Water  exists  not  only  in  the  ocean  and  in  lakes, 
rivers,  and  the  atmosphere,  but  is  widely  disseminated  in  a  solid, 
dry  state,  in  many  rocks  and  minerals.     The  waters  of  the  ocean 
are  sufficient  to  cover  the  earth  to  a  uniform  depth  of  more  than 
two  miles.     This  is  the  principal  repository  of  hydrogen,  includ- 
ing which  the  total  quantity  is  less  than  one  half  per  cent,  of  the 
earth's  crust. 

10.  Sodium  is  next  in  abundance,  and  exists  chiefly  in  common 
salt,  in  albite  and  in  basalt. 

11.  Next  is  Sulphur,  which  exists  in  a  free  state  in  volcanoes, 
but  most  abundantly  in  combination  with  many  metals,  as  iron, 
lead,  copper,  antimony,  &c.     It  also  enters  largely  into  the  com- 

What  is  said  of  iron  ?  of  carbon  ?  of  potassium  ?  of  hydrogen  ?  of  sodium  T 
of  sulphur?  &c. 


CHEMICAL    CONSTITUTION.  9 

oination  of  gypsum.    In  minute  proportions  it  is  diffused  through 
all  soils,  and  exists  in  all  animal  and  vegetable  bodies. 

12.  Manganese  is  almost  universally  disseminated  through  the 
rocks  and  soils,  but  with  an  average  proportion  not  exceeding 
TofoTtns  of  the  whole. 

13.  Chlorine  exists  mostly  in  common  salt,  and  in  the  chlorides 
of  magnesium  and  calcium  of  the  ocean.     It  is  universally  dis- 
seminated. 

14.  Phosphorus  exists  in  all  soils  in  small  proportion,  in  the 
bones  of  vertebrated  animals,  and  in  the  mineral  phosphate  of 
lime. 

15.  Fluorine  exists  chiefly  in  fluor  spar,  combined  with  calci- 
um ;  also  in  small  proportion  in  hornblende,  and  in  many  varie- 
ties of  mica,  and  consequently  in  most  of  the  unstratified  rocks. 

16.  Nitrogen  exists  chiefly  in  the  atmosphere  and  in  animal 
bodies,  and  is  generally  diffused  through  the  vegetable  kingdom 
in  small  proportion. 

These  simple  substances,  in  the  order  of  their  abundance,  are. 
oxygen,  about  fifty  per  cent. ;  silicon,  twenty-five  per  cent. ;  cal- 
cium, seven  per  cent. ;  aluminium,  five  per  cent. ;  magnesium, 
three  per  cent. ;  iron  and  carbon,  each  two  per  cent. ;  potassium, 
one  per  cent.  The  remaining  five  per  cent,  consist  mostly  of  hy- 
drogen, sodium,  sulphur,  manganese,  chlorine,  phosphorus,  fluor- 
ine, and  nitrogen. 

With  the  exception  of  nitrogen,  these  simple  substances  exist 
chiefly  or  solely  in  combination.  The  following  are  the  principal 
binary  compounds  in  the  order  of  their  abundance :  silica 
(quartz),  about  fifty  per  cent.;  alumina  and  lime,  each  ten  per 
cent. ;  carbonic  acid,  seven  per  cent. ;  magnesia  and  water,  each 
five  per  cent. ;  oxides  of  iron,  three  per  cent. ;  potash,  more  than 
one  per  cent.  Other  binary  compounds  are,  soda,  chloride  of  so- 
dium, sulphuret  of  iron,  oxide  of  manganese,  and  sulphuric  acid. 

Many  of  these  binary  compounds  unite  together,  and  form  salts 
or  ternary  compounds.  Such  are  carbonate  of  lime  and  carbon 

In  what  qaantity  do  these  substances  exist  ?  In  what  state  ?  What  are 
the  principal  binary  compounds  ?  What  are  ternary  compounds  ? 

A2 


10  CONSTITUTION    OP    THE    EARTH. 

ate  of  magnesia,  sulphate  of  lime,  the  silicates  of  potash,  of  soda, 
of  lime,  and  of  other  bases. 

II.  Mineral  Constitution  of  the  Earth. — As  a  book  is  com- 
posed of  letters  of  the  alphabet,  grouped  into  words  and  sen- 
tences, so  is  the  crust  of  the  earth  composed  of  many  distinct 
kinds  of  minerals,  which,  being  mixed  together,  constitute  rocks  ; 
and  many  of  the  rocks,  occurring  in  groups  of  strata,  with  certain 
distinctive  marks,  forming  separate  chapters  in  the  history  of  the 
globe,  constitute  what  are  called  formations. 

Minerals,  then,  are  the  alphabet  of  G-eology.  When  they  oc- 
cur in  homogeneous  masses,  they  are  called  simple  minerals  ; 
and  when  two  or  more  simple  minerals  have  been  mixed  togeth- 
er, they  form  a  rock.  In  a  few  cases,  a  simple  mineral,  as  lime- 
stone or  serpentine,  is  also  called  a  rock,  because  it  occurs  in  ex- 
tensive ledges. 

There  are,  in  the  crust  of  the  earth,  more  than  500  kinds  of 
simple  minerals  ;  and  if  a  knowledge  of  all  were  an  indispensa- 
ble preparation  for  the  study  of  Geology,  most  of  those  into  whose 
hands  this  work  may  come  might  well  be  discouraged.  Butjfoe 
only  of  these  minerals  constitute  about  nine  tenths  of  the  crust 
of  the  earth,  and  with  the  addition  of  two  or  three  more  the  num- 
ber will  embrace  nineteen  twentieths  of  the  crust. 

1.  Quartz  is  the  most  abundant  of  all  minerals,  constituting 
nearly  one  half  of  the  crust  of  the  earth.     It  is  one  of  the  harder 
minerals,  scratching  glass  with  facility,  although  inferior  to  the 
diamond.     When  regularly  crystallized,  it  is  called  rock  crystal, 
and  is  more  or  less  transparent.     Its  numerous  varieties  occui 
with  all  colors.     Flint  is  a  variety,  with  an  impalpable  structure 
acid  conchoidal  fracture.     The  presence  of  small  portions  of  iron, 
manganese,  chrome,  and  other  foreign  substances,  produces  nu- 
merous varieties,  some  of  which  are  valued  as  gems,  such  as  jas- 
per, amethyst,  agates,  cornelian,  &c.     The  sand  which  is  used  in 
making  mortar  and  glass  is  mostly  quartz. 

2.  Feldspar  constitutes  about  one  tenth  of  the  crust  of  the 

What  is  a  simple  mineral  ?  What  is  a  rock  ?  How  many  kinds  of  minerals 
aie  known  ?  How  ma  ly  are  abundant  ?  What  is  said  of  quartz  ?  of  feldspar? 


MINERAL    CONSTITUTION.  11 

earth.  It  is  less  glassy  in  its  appearance  than  quartz,  and  is  not 
quite  so  hard.  It  has  a  pearly  luster,  and  is  more  frequently  of 
a  grayish  white  color,  although  sometimes  red,  green,  &c.  When 
decomposed,  it  forms  an  unctuous  white  clay,  called  kaolin,  which 
is  of  great  use  in  the  manufacture  of  fire-bricks,  stone- ware,  pot- 
tery, and  porcelain.  The  undecomposed  mineral,  pulverized,  is 
used  with  kaolin  in  the  manufacture  of  the  finest  porcelain.  Com- 
mon clay  is  impure  decomposed  feldspar.  It  usually  contains  a 
small  portion  of'the  protoxide  of  iron,  which  by  heat  is  converted 
into  the  peroxide  of  iron,  a  red  substance,  which  giver  the  color 
to  common  bricks  and  pottery. 

3.  Limestone  (carbonate  of  lime)  forms  more  than  one  seventh 
of  the  crust  of  the  earth.     Its  varieties   are  numerous;  those 
which  are  crystallized  are  called  calcareous  spar.     It  is  much 
softer  than  quartz  or  feldspar,  being  easily  scratched.     Varieties 
which  admit  of  a  fine  polish  are  called  marble.     At  a  red  heat 
the  carbonic  acid  gas  is  expelled,  and  the  stone  becomes  lime. 
Marl  is  a  pulverulent  variety,  more  or  less  mixed  with  particles 
of  clay,  and  is  of  great  use  in  agriculture.     Calcareous  tufa  is  a 
deposit  of  this  mineral  from  mineral  springs.     Carbonate  of  lime 
is  easily  distinguished  from  other  common  minerals  by  the  ap- 
plication of  a  drop  of  acid,  which  will  produce  effervescence. 

4.  Hornblende,  including  augite,  which  is  now  regarded  as 
merely  a  variety  of  hornblende,  constitutes  a  large  part  of  the 
rocks  of  volcanic  origin,  and  of  some  of  the  older  slates.     It  forms 
from  one  fifteenth  to  one  twentieth  part  of  the  crust  of  the  earth. 
Some  of  its  varieties  are  beautiful  minerals,  as  actinolite,  amian- 
thus, &c.,  prized  by  the  mineralogist,  but  of  little  .economical 
value.     Asbestus  is  a  remarkable  variety,  consisting  of  excess- 
ively slender  silky  fibers,  that  may  be  picked  and  wove  like  cot- 
ton into  cloth,  which  will  be  incombustible.     It  may  also  be  used 
for  incombustible  lamp  wicks.    Compact  rocks,  of  which  this  min- 
eral forms  any  considerable  portion,  although  not  as  hard  as 
quartz  rocks,  are  exceedingly  tough. 

5.  Mica,  often  improperly  called  isinglass,  is  about  equally 

What  is  said  of  lirnestona  ?  of  hornblende  ?  of  mica? 


12  CONSTITUTION    OP   THE    EARTH. 

abundant  with  the  preceding.  It  is  not  very  hard,  and  usually 
occurs  in  thin  elastic  plates,  which  are  sometimes  found  contain- 
ing one  or  two  square  feet,  but  more  frequently  are  very  small, 
like  scales,  shining,  black,  brown,  or  silver  colored.  The  large 
sheets  are  used  for  lanterns,  stove-windows,  and  in  the  Russian 
navy  for  common  windows,  not  being  broken  by  the  concussion 
of  a  broadside. 

6.  Talc  is  one  of  the  softest  minerals,  being  very  easily.cut 
with  a  knife.     It  often  resembles  mica,  but  is  softer,  not  elastic, 
and  hap  tin  unctuous  feel.     It  contains  30  to  33  per  cent,  of  mag- 
ne-id.     One  of  its  varieties,  steatite  (soapstone),  occurs  in  extens- 
ive beds,  and  is  much  used  for  fire-places,  stove-linings,  &c. 
Talc  is  usually  light  green. 

7.  Chlorite  is  generally  dark  green,  and  differs  but  little  from 
talc. 

8.  Serpentine  is  usually  of  some  shade  of  green,  the  varieties 
of  lighter  color  being  called  precious  serpentine.     It  is  harder 
than  limestone.     It  receives  a  high  polish,  and  when  free  from 
the  cracks  and  seams  with  which  it  usually  abounds,  is  an  ele- 
gant substitute  for  marble. 

9.  Gypsum  (plaster),  rock  salt,  and  coal,  are  the  only  othei 
minerals  which  form  any  considerable  portion  of  the  earth's  crust 

III.  General  Structure  of  the  Earth. — By  the  crust  of  the  earth 
we  mean  that  portion  which  comes  within  the  reach  of  observa- 
tion and  legitimate  inference;  this  is  much  more  than  is  com- 
monly supposed  by  those  who  are  unacquainted  with  Geology. 
The  crust  is  composed  essentially  of  solid  rocks — the  loam,  sand, 
gravel,  clay,  and  other  soft  or  loose  materials,  being  merely  a  su- 
perficial covering. 

There  are  two  kinds  of  rocks,  differing  both  in  structure  and 
origin — the  stratified,  and  the  unstratified. 

The  stratified  rocks  occur  in  layers  or  strata,  and  were  depos- 
ited from  water.  Hence  those  which  lie  beneath  are  most  an- 
cient ;  and  where  two  kinds  of  stratified  rocks  occur  in  junction, 

What  is  said  of  talc  ?  &cl  What  is  meant  by  the  crust  of  the  earth  ?  What 
are  the  two  kinds  of  rocks  ?  What  is  said  of  stratified  rocks  ? 


«  STRUCTURE    OF    THE    EARTH*S    CRUST.  13 

the  one  lying  under  the  other,  their  relative  age  is  obvious.  By 
this  simple  principle  of  position,  the  relative  age  of  most  of  the 
rocks  has  been  determined.  The  various  circumstances  attend 
ing  the  deposition  may  also,  to  a  great  extent,  be  inferred  from 
the  character  of  the  strata.  Thin  layers  of  fine  materials,  and 
of  very  uniform  thickness,  are  deposited  from  quiet  water,  and 
those  which  consist  of  coarse  gravel  and  pebbles  are  the  products 
of  agitated  waters.  The  layers  of  the  stratified  rocks,  originally 
mud,  sand,  gravel,  shells,  coral,  &c.,  have  become  solid  by  the 
agency  of  heat,  pressure,  cohesion,  crystallization,  &c. 

The  unstratified  rocks,  on  the  other  hand,  usually  occur  in  ir- 
regular masses,  sometimes  overlaying  other  rocks,  or  in  veins 
cutting  across  the  layers  of  stratified  rocks,  or  forming  beds  in- 
terposed between  those  strata.  Modern  lavas  and  ancient  gran- 
ites are  alike  unstratified  and  of  igneous  origin — the  various  un- 
stratified rocks  having  been  erupted,  in  a  melted  condition,  at  dif- 
ferent periods  in  the  history  of  the  earth. 

The  unstratified  rocks  which  are  now  erupted  from  volcanoes 
have  their  source  beneath  all  other  known  rocks  ;  and  it  is  infer- 
red from  various  data,  that  those  of  ancient  date  were  in  like 
manner  erupted  from  beneath  the  then  existing  rocks.  Going 
far  back  in  the  geological  history  of  the  globe,  we  come  to  a  pe- 
riod when  the  lowest  and  oldest  stratified  rock  rested  alone  upon 
granite,  the  oldest  of  the  unstratified.  Beneath  are  doubtless,  in 
immense  irregular  beds,  the  reservoirs  whence  the  eruptions  of 
the  igneous  rocks  had  their  origin,  and  above  we  have  the  suc- 
cessive strata,  whose  contents  reveal  the  physical  history  of  the 
earth. 

A  general  idea  of  the  structure  of  the  earth  may  be  obtained 
from  the  following  figure,  which  is  not  intended  to  represent  any 
given  region,  but  is  an  ideal  exhibition  of  the  positions  of  the 
rocks  as  they  would  appear  in  a  section  through  the  crust  of  the 
earth.  A  little  attention  to  the  explanations  will  supersede  the 
necessity  of  a  lengthened  description. 

What  is  said  of  the  mode  in  which  the  unstraidfied  rocks  occur  ?  of  their 
•ource? 


14 


CONSTITUTION    OP   THE    EARTH. 


I<  Unstratified  Rocks,  of  igneous  Origin. —  G.  Granite.  Sn.  Syenite.  Pr. 
Porphyry.  Tp.  Trap  rocks.  Td.  Trap  dike.  L.  Lava,  c,  c.  Fissures  through 
which  the  water  of  the  ocean  penetrates  to  the  melted  lava. 

2.  Stratified  Rocks,  of  aqueous  Origin,  represented  by  parallel  lines. — M. 
Metamorphic  rocks.  Pz.  Palaeozoic  rocks,  or  the  oldest  rocks  which  contain 
the  remains  of  animals  and  plants.  Mz.  Mesozoic  rocks.  Tt.  Tertiary  strata 
D.  Superficial  covering  of  sand,  gravel,  and  loose  stones. 


PART    I. 


GEOLOGICAL  AGENCIES. 

WITH  a  constitutional  belief  in  the  constancy  of  the  laws  of 
nature,  we  look  to  the  operations  now  in  progress,  not  only  on 
account  of  their  intrinsic  interest,  but  because  they  alone  can  en- 
able us  to  understand  the  history  of  the  past.  When  we  have 
seen  strata  in  the  process  of  accumulation  beneath  the  waters, 
burying  within  them  the  present  races  of  animals  and  plants, 
marine,  fluviatile,  or  terrestrial,  the  species  of  hot  or  those  of 
cold  climates,  according  to  the  situation  in  which  these  deposits 
are  forming;  and  when  we  have  seen  unstratified  rocks  result- 
ing from  eruptions  of  lava,  we  shall  be  better  able  to  compre- 
hend the  origin  of  ancient  deposits,  with  their  imbedded  relics  of 
species  which  have  long  been  extinct,  and  of  those  enormous 
masses  of  unstratified  crystalline  rocks  which  exist  where  the 
volcanic  fires  have  long  since  gone  out. 

Classification  of  Geological  Agencies.  —  Geological  agencies 
may,  for  the  most  part,  be  referred  to  three  heads :  the  igneous, 
comprehending  all  the  effects  of  heat ;  the  aqueous,  including  the 
effects  of  water  in  all  its  forms ;  and  the  organic,  or  agency  of 
the  animal  and  vegetable  kingdoms. 

Intensity  of  Geological  Agencies. — Some  very  able  geologists 
are  of  the  opinion  that  the  course  of  nature  has  been,  through 
all  the  geological  epochs,  the  same  as  at  the  present,  not  only  in 
the  nature  of  the  agencies  of  change,  but  also  in  the  degree  of 
intensity  with  which  they  have  acted  ;  that  volcanic  forces  have 
never  been  more  violent  than  they  are  now ;  and  that  there  have 
been  no  other  changes  of  climate  than  those  which  are  conse- 
quent on  changes  in  the  relative  distribution  of  land  and  water. 

What  are  the  principal  agencies  now  active  in  modifying  the  crust  of  the 
earth  ?  On  what  points  do  geolog'sts  differ  7 


16  AaUEOUS    AGENCIES. 

Many  others  suppose  that  volcanic  convulsions  of  the  earth's  crust 
have  been  more  violent  and  on  a  larger  scale  than  at  present;  and 
that  the  earth's  surface  was  once  intensely  heated  by  the  internal 
fires,  and  after  a  partial  reduction  of  temperature,-  was  adapted 
for  the  support  of  the  dense  tropical  vegetation  and  the  tropical 
races  of  animals,  whose  remains  are  now  found  abundantly  in  cold 
climates.  Without  discussing  this  question  at  present — the  only 
elementary  question  on  which  geologists  differ — we  merely  hold 
it  up,  that  it  may  be  seen  in  the  light  of  the  facts  which  we  are 
briefly  to  notice. 

This  difference  of  opinion,  which  is  gradually  diminishing  by 
an  approach  to  a  medium,  it  is  important  to  observe,  relates  only 
to  the  energy  of  the  geological  agencies  of 'former  periods.  It  is 
admitted  by  all  that  these  agencies  have  ever  been  of  the  same 
nature  as  at  present. 


CHAPTER  I. 

AQUEOUS   AGENCIES. 

THE  aqueous  agencies,  which  are  modifying  the  surface  of  the 
earth,  act  both  chemically  and  mechanically.  Their  chemical 
effects  are  limited  chiefly  to  the  solution  of  rocks.  Mechanically 
their  action  is  more  various  and  extensive.  By  penetrating  por- 
ous rocks,  and  by  circulating  in  the  form  of  rivers,  tides,  waves, 
marine  currents,  glaciers,  and  icebergs,  water  is  continually  rend 
ing  the  rocks  into  fragments,  and  removing  the  materials  to  low 
er  levels,  or  into  the  ocean.  With  yet  greater  facility  are  mate- 
rials carried  down  which  have  been  dissolved  in  water.  The 
general  tendency  of  aqueous  action  is,  therefore,  to  transport  the  con- 
tinents  into  the  ocean. 

The  ocean  covers  more  than  two  thirds  of  the  surface  of  the 
globe,  and  the  rise  of  water  consequent  on  the  transport  of  mate- 

What  is  said  of  the  chemical  effects  of  aqueous  agencies  ?  of  their  mechan* 
ical  effects?  of  their  general  tendency? 


AQUEOUS    AGENCIES    NOT    MARJNE.  17 

rials  into  the  ocean  tends  materially  to  increase  its  extent  at  the 
expense  of  the  existing  continents.  There  would,  therefore,  be 
at  length  a  universal  inundation,  if  the  sinking  of  the  bed  of  the 
ocean  and  the  elevatory  agencies  of  igneous  action  did  not  tend 
in  an  equal  or  greater  degree  to  diminish  its  area. 

Aqueous  agencies  may  be  classified  as  they  are  or  are  not  ma- 
rine. 

Those  which  are  not  marine  are  the  atmospheric  agencies  of 
rain  and  frost,  rivers,  lakes,  springs,  and  glaciers. 

The  marine  agencies  are  icebergs,  waves,  tides,  and  oceanic 
currents. 

SECTION  I.— AQUEOUS  AGENCIES  NOT  MARINE. 

I.  Atmospheric  Agencies. — 1.  Rain  acts  chemically  on  all  cal- 
careous rocks.  It  is  well  known  that  .water,  when  pure,  will  not 
dissolve  limestone,  but  that,  when  charged  with  carbonic  acid  gas, 
it  will  dissolve  calcareous  matter  with  a  facility  proportionate  to 
the  quantity  of  gas  in  the  water.  Falling  rain  absorbs  this  gas 
from  the  air,  and  thus  acquires  the  power  of  slowly  dissolving  the 
solid  rocks  in  limestone  countries.  Calciferous  rocks  exhibit  the 
effect  of  this  action  in  the  irregular  furrows  which  are  worn  down 
their  inclined  sides,  and  in  their  more  or  less  rounded  surfaces. 
Rain  also  promotes  the  union  of  oxygen  and  carbonic  acid  with 
the  iron  of  iron  pyrites,  and  thus  causes  rocks  which  contain  this 
mineral  to  crumble.  In  a  similar  manner  it  acts  on  other  metals, 
and  on  the  common  alkalies,  potash  and  soda,  in  such  feldspath- 
ic  rocks  as  granite  and  syenite.  The  chemical  part  of  this  pro- 
cess is  called  decomposition.  The  mechanical  effect  in  the  crum- 
bling of  rocks  is  called  disintegration.  Rocks  which  contain  py- 
rites and  alkalies  abundantly  are  therefore  most  affected  in  this 
manner.  The  effect  is  much  greater  when  a  porous  or  fissured 
structure  allows  the  rain  to  penetrate  far  into  the  rock. 

Rains  also  act  mechanically  by  carrying  the  loose  fragments 
and  particles  on  the  surface  of  the  ground  into  rivers,  thus  fur- 
How  are  aqueous  agencies  classified  ?     Describe  the  action  of  rain.     What 
is  decomposition  ?     What  is  disintegration  ? 


18  AGENCY    OF    FROST. 

mshing  them  not  only  with  their  liquid,  but  also  with  their  solid 
contents. 

This  agency  is  very  striking  in  some  countries,  where  the  rock 
formations  are  more  or  less  porous  like  sandstone,  or  where  they 
have  not  been  first  worn  and  then  protected  by  drift.  In  Jamai- 
ca and  Antigua,  there  is  often  an  imperceptible  gradation  of  co- 
herence from  the  loose  soil  of  the  surface  to  the  solid  rock  be 
neath,  and  the  upper  portions  of  the  latter  may  easily  be  removed 
with  a  spade.  Heavy  rains  falling  on  the  steep  sides  of  mount- 
ains of  such  rocks  will,  therefore,  carry  off  immense  quantities  of 
matter,  and  expose  fresh  portions  of  rock. 

The  removal  of  mineral  matter  from  higher  to  lower  stations 
is  the  greater  from  the  fact  that  a  greater  quantity  of  rain  usu- 
ally falls  on  high  than  on  low  lands.  Elevated  districts,  being 
cooler,  condense  a  greater  portion  of  the  vapor,  which  is  every 
where  present  in  the  atmosphere.  This  is  especially  manifest  in 
hot  countries,  where  the  intense  heat  enables  the  air  to  contain 
an  immense  amount  of  watery  vapor,  which  is  condensed  in  del 
uging  showers  on  the  sides  of  the  mountains. 

2.  Frost  is  another  atmospheric  agency,  which  in  cold  climates 
more  or  less  compensates  for  the  deficiency  of  rain  in  the  work 
of  destruction.  Water  penetrating  into  porous  rocks,  or  enter- 
ing fissures  and  expanding  by  frost  with  an  irresistible  force, 
crumbles  the  surface,  and  throws  out  large  blocks  of  stone.  The 
fragments  lie  in  enormous  heaps  at  the  base  of  precipices,  or  fall 
into  the  beds  of  mountain  torrents,  and  are  removed  by  freshets. 
Such  an  accumulation  of  angular  blocks  at  the  foot  of  a  precipice 
is  called  a  talus,  and  usually  has  an  inclination  of  about  40°. 

A  very  compact  structure  almost  wholly  preserves  a  rock  from 
this  mechanical  agency,  and  a  covering  of  clay  preserves  it  also 
from  the  chemical  action  of  water.  In  the  valley  of  the  Con- 
necticut, porous  sandstones  have  been  penetrated  and  altered  to 
the  depth  of  ten  feet.  Granite  and  syenite  often  have  a  discolor- 
ed exterior  of  only  one  or  a  few  inches.  But  on  compact  varie- 

Describe  the  action  of  frost.  Meaning  of  talus  ?  To  what  depth  imv» 
rocks  been  acted  upon  by  water  ? 


NIAGARA    FALLS.  19 

ties  of  greenstone,  the  altered  exterior  is  but  a  small  fraction  of 
an  inch  in  thickness,  and  those  striae  are  retained  which  were 
made  by  glacial  agency  in  a  period  long  anterior  to  any  human 
history.  In  the  valley  of  Lake  Champlain,  marbles  which  were 
polished  and  striated  by  the  glacial  agency,  and  then  covered 
with  clay,  are  found,  when  now  uncovered,  to  retain  not  only  the 
finest  striae,  but  their  brilliancy  of  polish. 

II.  Rivers. — Rivers  co-operate  in  the  work  by  carrying  down 
limestone  in  solution,  thus  furnishing  the  materials  for  the  solid 
structures  of  some  of  the  most  extensive  and  interesting  organic 
agencies  which  we  are  to  notice.  Their  most  obvious  action, 
however,  is  in  the  transport  of  matter  merely  by  mechanical  agen- 
cy. This  is  much  greater  than  some  would  suppose,  from  the 
fact  that  mineral  substances  lose  about  three  sevenths  of  their 
weight  in  water  as  compared  with  their  weight  in  air.  A  cur- 
rent moving  with  a  velocity  of  only  300  yards  per  hour,  will  tear 
up  fine  clay  ;  of  600  yards  per  hour,  will  remove  fine  sand ;  of 
two  thirds  of  a  mile  per  hour,  will  remove  coarse  sand  ;  and  with 
a  velocity  of  two  miles  per  hour,  will  transport  stones  two  inches 
in  diameter.  The  agency  of  running  water  is  also  multiplied  by 
the  friction  of  the  transported  fragments  upon  each  other  and  on 
the  bed  of  the  stream. 

One  of  the  most  magnificent  and  instructive  examples  of  the 
denuding  agency  of  rivers  is  to  be  seen  in  the  retrocession  of  the 
Niagara  Falls,  which  have  cut  an  enormous  ravine  from  Queens- 
town,  seven  miles  back,  to  their  present  situation.  Soft  shales  at 
the  base  of  the  falls  underlie  the  harder  limestone,  which  is  grad- 
ually undermined,  and  fragments  of  the  overlying  rocks  are  de- 
tached from  above.  In  this  way  the  falls  are  now  retrograding 
at  a  rate  not  easily  reckoned  with  precision  for  the  want  of  his- 
torical data,  but  variously  estimated  to  average  from  one  foot  to 
one  yard  per  year.  As  the  rocks  have  a  small  dip  backward  in 
the  direction  of  Lake  Erie,  the  water  will  at  length  cease  to  act 
on  the  soft  shales  for  the  want  of  sufficient  fall  below  to  remove 
the  materials.  The  process  will  therefore  be  arrested  long  be- 
fore the  falls  can  have  traveled  back  as  far  as  the  lake. 

In  what  manner  d<r  nvers  act  ?     Describe  the  action  of  Niagara  River  at  the 


20 


AGENCY    OP    RIVERS. 

Fig.  2. 


VIEW  OF  NIAGARA  FALLS. 

In  crossing  the  river  just  below  the  falls,  the  view  is  justly  re- 
garded as  one  of  the  most  sublime  in  the  natural  world.  As  you 
look  up  from  this  deep  ravine,  you  see  at  least  20,000,000  cubic 
feet  of  water  each  minute  rushing  down  from  a  height  of  160  feet, 
and  appearing  in  truth 

"  As  if  God  poured  it  from  his  '  hollow  hand,' 

*  *  *  *  and  had  bid 

Its  flood  to  chronicle  the  ages  back, 

And  notch  his  centuries  in  the  eternal  rock." 

A  remarkable  example  of  rapid  erosive  action  of  water  is  found 
at  the  lower  falls  of  the  Genesee  River,  at  Portage,  N.  Y.  It  is 
within  the  recollection  of  some  of  the  inhabitants  that  the  river 
flowed  over  a  table  rock,  and  was  precipitated  96  feet  to  the  level 
of  the  river  below  the  falls.  There  is,  however,  now  a  channel 
extending  back  from  the  falls  one  eighth  of  a  mile,  80  feet  wide 
and  deep,  forming  a  violent  rapid,  down  which  the  water,  bear- 
ing along  ice  and  debris,  rushes  and  rapidly  wears  away  the  solid 
rocks.  Within  five  years  it  is  known  to  have  deepened  in  some 
places  five  or  six  feet  (Fig.  3). 

In  1603  a  current  of  lava  flowed  down  from  the  highest  sum- 

What  is  said  of  Genesee  River  ? 


THE    GANGES    AND    BURRAMPOOTER. 


LOWER    FALLS    OF    PORTAGE,   N.  T. 

rnit  of  JEtna,  on  the  west  side,  into  the  valley  of  the  Simeto,  and 
completely  blocked  up  the  beds  of  the  river.  In  the  course  of 
cOO  years  the  stream  has  worn  through  this  lava,  which  is  a  com 
pact  blue  rock,  a  passage  from  fifty  to  several  hundred  feet  wide, 
and  from  forty  to  fifty  feet  deep. 

The  Ganges  and  Burrampootcr,  descending  from  the  Hima- 
laya Mountains,  the  loftiest  on  the  globe,  unite  in  a  vast  delta 
which  they  have  formed.  This  delta  is  an  extensive  alluvial 
plain,  reticulated  by  an  immense  number  of  channels,  and  is 
more  than  half  as  large  as  the  State  of  New  York.  Nothing  as 
coarse  as  gravel  can  be  found  near  the  Ganges  within  400  miles 
)f  its  mouth.  The  river  has  been  known  to  carry  away  40 
•square  miles  from  one  district  within  a  few  years.  Islands  of 
many  miles  in  extent  are  formed  in  a  short  period.  Various  es- 
timates have  been  made  of  the  quantity  of  the  solid  matter  which 
is  carried  down  bv  this  river ;  according  to  the  most  accurate  of 
which,  35,000  cubic  feet  of  mud  pass  down  every  minute  during 
the  flood  season,  or  about  3,500,000  tons  daily,  and  the  quantity 
discharged  during  the  120  days  of  the  flood  must  therefore 
amount  to  6,000,000,000  of  cubic  feet.  High  tides  (11  to  16 
feet)  rapidly  disperse  this  sediment  in  the  Bay  of  Bengal,  whose 

What  is  said  of  the  Simeto  ?  the  Ganges  and  Burrampooter  ?  What  amount 
of  matter  does  the  Ganges  transport  ? 


22  AGENCY    OF    RIVERS 

waters.  100  fathoms  deep  at  100  miles  out,  are  gradually  shoaled 
from  this  distance  toward  the  shore  to  four  fathoms,  and  for  60 
miles  are  discolored  by  this  turbid  stream.  The  annual  discharge 
of  the  Ganges  would  be  sufficient  to  cover  a  township  six  miles 
square  with  soil  to  the  depth  of  nearly  seven  feet. 

The  delta  of  the  Nile  is  nearly  as  large  as  the  State  of  Vermont. 
Its  progress  has  been  arrested  in  comparatively  modern  times  by 
an  easterly  current  in  the  Mediterranean,  which  carries  off  much 
of  the  sediment  that  is  discharged  into  the  sea,  and  preys  occa- 
sionally upon  the  delta  itself.  It  is  very  probable  that  a  bay  once 
occupied  the  site  of  the  delta,  and  that  it  must  have  been  of  great 
depth,  for  while  the  sea  near  the  shore  gradually  deepens  to  50 
fathoms,  it  then  suddenly  falls  off  to  380  fathoms. 

The  Amazon  is  probably  unequaled  among  all  the  powerful 
agents  of  degradation.  The  vast  amount  carried  out  by  its  cur- 
rent, which  is  not  entirely  lost  in  the  ocean  at  the  distance  of  306 
miles  from  land,  is  furnishing  materials,  which,  instead  of  form- 
ing a  delta,  become  the  subjects  of  oceanic  agents. 

The  Mississippi,  the  father  of  waters,  has  formed  most  of  the 
lower  part  of  Louisiana,  and  is  forming  a  tongue  of  land  which 
extends  far  into  the  G-ulf  of  Mexico,  and  which  has  advanced  sev- 
eral leagues  since  New  Orleans  was  built.  The  annual  discharge 
of  this  river  is  14,883,360,000,000  cubic  feet,  equal  to  101-1  cubic 
miles  of  water.  This  is  about  one  twelfth  part  of  the  quantity 
of  rain  which  falls  in  its  valley,  the  remaining  eleven  twelfths 
being  lost  by  evaporation.  The  average  amount  of  sediment  is 
-jigth  part,  making  28,188,000,000  cubic  feet,  or  2,000,000,000 
tons  of  solid  matter.  This  annual  deposit  would  be  sufficient  to 
cover  a  township  six  miles  square  to  the  depth  of  30  feet.  The 
delta  comprises  an  area  of  13,000  square  miles,  with  a  probable 
depth  of  not  less  than  1000  feet.  This  amounts  to  2700  cubic 
miles,  and  would  have  required  14,000  years  for  its  deposition, 
if  all  the  sediment  had  fallen  within  its  area  during  this  time. 
Since,  however,  a  considerable  portion  has  been  more  widely  dis- 
tributed in  the  Gulf  of  Mexico,  the  age  of  the  delta  must  be  much 
greater. 

In  Massachusetts,  the  matter  carried  down  by  the  Merrimac 
hai  been  estimated,  from  careful  experiments  by  Dr.  S.  L.  Dana, 
of  Lowell,  to  be  840,000  tons  per  annum. 

The  destructive  force  of  occasional  floods  and  storms  is  wor« 
thy  of  notice.  Oceanic  deltas  are  liable  to  be  flooded  not  only 

What  is  said  of  the  Nile?  the  Amazon?  the  Mississippi?  the  Merrimac f 
In  what  manner  do  floods  increase  this  action  ? 


CHANGES    OP    THE    CHANNELS    OF    RIVERS.  23 

by  freshets,  but  by  storms  from  the  sea,  driving  up  the  tide  and 
current,  and  when,  at  rare  intervals,  these  causes  all  combine,  ex 
tensive  tracts  are  entirely  remodeled,  and  vegetable  and  animal 
life  perish  on  a  scale  commensurate  with  the  changes  in  inorgan- 
ic nature. 

Tropical  mountainous  regions  are  especially  liable  to  very  de 
structive  floods,  which  pour  down  in  continuous  cataracts,  sweep- 
ing along  rocks  of  many  tons'  weight,  where  ordinarily  an  insig- 
nificant brook  only  is  to  be  seen.     Temporary  rivers  are  then 
formed  where,  in  dry  seasons,  water  is  entirely  wanting. 

Masses  of  ice  co-operate  powerfully  with  freshets,  choking  up 
the  course  of  the  stream,  and  forming  basins  of  the  accumulated 
waters,  which  at  length  burst  their  barriers,  and  rush  down,  tear- 
ing up  the  loose  earth  in  narrow  gorges,  like  Deerfield  River  in 
Massachusetts,  and  grinding  over  the  solid  rocks  with  the  noise 
of  thunder. 

The  tendency  of  a  river  flowing  through  a  plain  of  un consoli- 
dated materials  is  to  form  curves,  or  bends,  as  they  are  usually 
called.  Wherever  the  current  deviates  from  a  straight  line,  it/\ 
strikes  the  opposite  bank,  wearing  it  away,  while  the  compara- 
tive quietness  of  the  water  on  the  other  side  promotes  the  accu- 
mulation of  sediment,  and  the  degree  of  curvature  is  thus  contin- 
ually increasing.  At  length,  in  some  unusual  freshet,  the  river 
cuts  across  the  narrowed  neck  of  the  bend  and  forms  a  new  chan- 
nel. Such  bends  are  numerous  oft  the  Mississippi,  and  are  fre- 
quently cut  off.  A  few  years  since,  a  remarkable  bend  in  the 
Connecticut,  in  the  beautiful  alluvial  meadows  of  Northampton, 
had  a  circuit  of  about  three  miles,  with  a  neck  of  eighty  rods,  when 
in  a  freshet  the  river  cut  a  deep  channel  across  the  neck,  leaving 
its  former  circuit  dry  except  so  far  as  it  still  receives  a  small  trib- 
utary. 

Poultney  River,  in  Vermont,  affords  a  very  remarkable  exam- 
ple of  a  change  of  channel  near  Fairhaven.  The  change  occur- 
red in  1783,  during  a  freshet,  and  the  neighboring  inhabitants 

What  phenomena  are  presented  by  rivers  flowing  through  plains  ?  What 
is  said  of  tropical  regions  ?  of  the  effects  of  ice  ? 


•4  AGENCY   OP    RIVERS. 

say  that  it  was  caused  by  running  a  furrow  across  the  neck  (*  » 
in  the  figure)  of  a  peninsula. 

The  accompanying  figure  is  referred  to  in  this  description,  the 
present  channel  being  represented  by  continuous,  and  the  former 
by  dotted  lines. 

Fig.  4. 


B  B  B  B  are  hills  of  taconic  slate ;  A  A  A  A  is.  an  alluvial  plain, 
overflowed  before  1783,  and  overlying  a  thick  deposit  of  fine 
blue  clay. 

a  a  are  the  Dry  Falls,  which  are  about  150  feet  high,  and  fif- 
teen rods  long.  The  water  was  precipitated  over  the  edges  of 
the  strata  of  soft  slate.  On  the  lower  parts  of  the  projecting 
strata  are  numerous  deep  fiwrows,  mostly  about  a  foot  long,  four 
to  five  inches  wide,  and  two  inches  deep,  but  somewhat  deepei 
in  the  middle.  There  are  also  several  pot-holes  of  various  sizes. 

n  n  is  recent  alluvial  deposit.  Further  up  the  stream  we  find 
high  banks  of  clay,  and  in  the  plain  A  A  the  river  has  cut  through 
alluvium  and  blue  clay  to  a  depth  of  one  hundred  and  fifty  feet 


RIVER    VALLEYS.  25 

Immense  slides,  on  either  side  of  the  tortuous  stream,  cover  an 
area  of  several  square  miles  with  a  scene  of  violent  disturbance. 
c  c  was  an  island  in  the  old  channel,  m  is  a  small  rivulet 
which  formerly  emptied  intp  the  river  at  r,  and  now  runs  back 
through  the  old  channel  to  x,  having,  since  1783,  cut  the  channe/ 
on  the  north  side  of  the  island,  c  c,  to  a  great  depth.  The  old 
channel  is  now  covered  with  grass.  It  was  only  about  ten  feet 
below  the  banks,  the  rocks  at  the  falls  having  been  a  barrier 
which  prevented  a  deeper  cut. 

Numerous  rivers,  in  the  lower  part  of  their  channels,  have 
probably  ceased  the  work  of  excavation,  and,  when  confined  by 
embankments,  have  a  tendency  to  fill  up  their  beds  and  run  at 
higher  levels.  The  Po  and  the  Adige  drain  the  northern  part  of 
Italy,  and  have  caused  one  hundred  miles  of  coast  to  encroach 
twenty  miles  upon  the  Adriatic  Sea  within  2000  years.  On  these 
rivers  the  practice  of  embankment,  which  commenced  in  the  thir- 
teenth century,  has  been  carried  to  a  great  extent.  In  conse- 
quence, the  Po  has  been  filled  up  so  much  that  the  surface  of  the 
water  is  higher  than  the  roofs  of  the  houses  in  the  city  of  Ferra- 
ra.  The  magnitude  of  these  barriers  is  a  subject  of  increasing 
expense  and  anxiety,  it  having  sometimes  been  found  necessary 
to  give  them  an  additional  height  of  one  foot  in  a  single  season. 
The  Mississippi  is  confined  by  levees  for  a  considerable  distance 
above  and  below  New  Orleans,  and  the  future  inhabitants  of  Lou- 
isiana may  find  the  river  rather  unmanageable,  should  it  begin  to 
fill  its  bed  and  to  raise  its  waters.  In  consequence,  however,  of 
die  increased  evaporation  resulting  from  the  clearing  of  forests 
about  the  sources  of  the  river,  it  is  said  that  the  annual  discharge 
has  sensibly  diminished  within  fifty  years.  In  a  small  degree, 
however,  the  levees,  by  preventing  the  expansion  of  the  river  in 
freshets,  diminish  evaporation. 

Notwithstanding  the  powerful  degrading  agency  of  rivers,  they 
have  not,  in  most  cases,  formed  the  valleys  through  which  the} 
flow.  These  are  usually  due  to  agencies  which  gave  the  con 
figuration  to  the  surface  of  the  earth  long  anterior  to  the  historic- 
al epoch.  Some  rivers,  as  may  be  seen  in  Fig.  5,  turn  aside  from 
valleys,  through  which  a  moderate  elevation  would  send  them, 

What  is  said  of  the  Po  ?  of  the  Adige  f  of  the  Mississippi  ?  of  river  valleys  ? 

B 


26  BURSTING    OF    LAKES. 

to  pass  through  mountain  gorges,  which  must  have  been  made  by 
other  agencies.  But  the  terraces  so  frequently  seen  on  our  riv- 
ers were  mostly  formed  by  their  degrading  agency  in  a  former 
period,  in  the  history  of  which  we* shall  explain  the  mode  of 
their  formation. 

Fig.  5. 


a  a  a  a,  a  valley,  which  is  crossed  by  Deerfield,  "Westfield,  and 
Farmington  rivers,  c,  t,  i,  and  G,  are  greenstone  ridges.  H, 
Mount  Holyoke  ;  T,  Mount  Tom. 

III.  Bursting  of  Lakes. — The  bursting  of  lakes  is  an  agency 
which,  although  occasional  and  rare,  produces  powerful  effects. 

A  frightful  deluge  occurred  in  1818  in  the  valley  of  Bagnes,  in 
Switzerland.  The  waters  of  the  Drance  were  dammed  up  by 
the  falling  of  glaciers  and  avalanches,  which  formed  a  barrier  400 
feet  high  and  600  feet  wide,  above  which  a  lake  nearly  a  mile 
and  a  half  long  accumulated.  A  bold  and  persevering  engineer 
tunneled  the  dike  so  as  to  meet  the  surface  of  the  water  of  the 
lake,  which  flowed  through,  gradually  melting  down  its  channel 
as  the  water  fell  in  the  lake.  In  this  way  330,000,000  cubic 
feet  of  water  were  carried  off  in  three  days  without  damage,  when 
the  dike  gave  way,  and  in  half  an  hour  530,000,000  cubic  feet  of 
water  swept  down,  running  the  first  thirteen  miles  in  thirty-five 
minutes,  and  bearing  down  400  houses,  with  trees,  rocks,  and 
earth.  Had  it  not  been  for  the  enterprise  of  the  engineer,  three 
times  the  amount  of  water  might  have  accumulated  before  burst- 
ing through  the  dike. 

Similar  to  this  was  the  eruption  of  Long  Pond,  in  Glover,  Ver- 
mont. A  barrier  of  fine  sand  separated  this  pond  from  the  val- 
ley, which  extended  20  miles  to  Lake  Memphremagog.  Some 
persons  having  made,  for  amusement,  a  small  channel  through 

Describe  the  effects  of  the  bursting  of  lakes. 


AGENCY    OP    SPRINGS.  27 

the  sand  barrier,  the  running  water  in  a  few  minutes  excavated 
the  channel  deep  enDugh  entirely  to  empty  the  pond.     The  water 
rushed  into  Barton  River,  the  channel  of  which  was  much  en 
larged  by  the  violent  inundation,  and  great  numbers  of  trees  were 
carried  down  the  stream. 

IV.  Springs. — Springs  act  chiefly  by  taking  up  mineral  mattei 
at  various  depths,  and  afterward  depositing  it  on  the  surface  of 
the  ground.  The  deposits  of  greatest  magnitude  are  calcareous 
or  silicious.  We  have  already  remarked  that  water  which  con- 
tains carbonic  acid  has  the  property  of  dissolving  limestone. 
Now  the  quantity  of  this  gas  which  water  is  capable  of  containing 
depends  upon  pressure.  Under  the  pressure  of  the  atmosphere 
it  may  contain  its  own  volume ;  if  the  pressure  be  doubled,  it 
will  take  up  double  its  volume,  and  so  on,  and  to  any  additional 
amount  in  proportion  to  the  pressure.  Consequently,  at  some 
distance  beneath  the  surface  of  the  earth,  springs  may,  and  espe 
cially  in  limestone  countries  do,  contain  a  great  amount  of  this  gas 
Hence  the  subterranean  passage  of  such  water  through  fissures 
in  limestone  enlarges  those  fissures,  so  that  in  many  cases  rivers 
of  considerable  size,  as  in  Jamaica  (West  Indies),  after  flowing 
on  the  surface  for  many  miles,  are  lost  in  limestone  chasms  and 
flow  under  ground.  Caverns  of  greater  or  less  size  are  formed 
by  the  same  agency,  for  caves  of  any  considerable  extent  are  al 
most  invariably  in  limestone  districts. 

The  water,  if  overcharged  with  gas  and  limestone,  that  is,  con 
taining  more  than  the  mere  pressure  of  the  air  will  permit,  must 
deposit  the  excess  of  limestone  when  it  issues  either  into  an  open 
cavern  or  upon  the  surface  of  the  ground.  When  it  drops  from' 
the  roof  of  a  cavern,  stalactites  are  formed,  like  icicles  pendent 
from  the  roof,  and  masses  of  stalagmite  on  its  floor,  and  some- 
times these  meet,  forming  a  column,  which  is  continuous  from 
the  floor  to  the  roof  of  the  cavern.  Sometimes  these  masses,  es- 
pecially the  stalactites,  are  of  a  beautiful  crystalline  structure; 
the  stalagmite  is  more  frequently  in  thin  concentric  but  irregulai 
layers,  a  result  of  the  mode  cf  its  deposition.  Masses  of  the  latter 

Describe  the  action  of  springs ;  the  formation  of  stalactites. 


28  LANDSLIDES. 

have  been  seen  rising  up,  like  altars,  10  or  12  feet  high,  and  15 
feet  in  diameter.  Slabs  of  beautiful  calcareous  alabaster  are  ob- 
tained from  such  stalagmite. 

The  most  extensive  deposits  of  this  kind  are  formed  where 
the  springs  issue  on  the  surface  of  the  ground.  At  San  Filippo, 
in  Italy,  the  springs  have  deposited  a  mass  of  limestone  250  feet 
thick,  and  a  mile  and  a  quarter  in  length.  These  springs  have 
been  known  to  deposit  a  solid  mass  30  feet  thick  in  20  years. 
The  High  Rock  at  Saratoga,  N.  Y.,  is  a  calcareous  deposit  from 
tne  spring  in  its  center.  The  geologist  is  familiar  with  numerous 
cases  like  this.  Frequently  the  calcareous  deposits  of  springs 
are  more  or  less  filled  with  irregular  pores,  and  the  mass  is  then 
called  tufa.  Plants,  and  any  other  bodies  lying  in  the  water  of 
such  springs,  are  liable  to  be  coated  with  the  deposit,  and  such 
cases  of  mere  incrustation  are  sometimes  confounded  with  petri- 
faction, which  is  an  entirely  different  process. 

Deposits  of  silicious  matter,  often  called  silicious  sinter,  are 
the  product  of  hot  springs.  If  water  contains  an  alkali,  as  soda, 
it  is  capable,  especially  at  a  high  temperature,  of  dissolving  silex, 
which  is  deposited  when  the  spring  comes  to  the  surface,  The 
basin  of  the  Great  Geyser,  in  Iceland,  has  been  formed  in  this 
manner.  Silicious  incrustations  are  formed  on  plants  in  the  same 
manner  as  the  calcareous  incrustations  above  mentioned.  Such 
deposits  a.re  less  numerous  and  extensive  than  those  which  are 
calcareous,  but  are  of  much  interest,  as  showing  us  how  water 
may  dissolve  rocks  of  flint. 

V.  Landslides. — Landslides  frequently  occur  on  mountains,  es- 
pecially in  times  of  freshets,  and  sometimes  fill  up  the  course  of 
streams  and  occasion  floods.  Hills  of  clay  are  peculiarly  liable 
to  slides,  which  produce  contortions  in  the  flexible  strata.  Ava- 
lanches of  snow  and  ice  concur  in  violently  removing  rocks  and 
earth  from  the  steep  sides  of  mountains  into  valleys  beneath. 
The  pressure  of  water  in  fissures,  the  undermining  process  of 
water  passing  through  soft  strata,  the  action  of  springs,  convert- 
Mention  examples.  What  is  silicious  sinter?  Describe  the  Great  Geyser 
What  is  *&.•*.  or' landslides  ?  of  their  origin  ? 


GLACIERS THEIR    ORIGIN.  29 

ing  sand  into  quicksand,  the  eroding  power  of  streams  and  tor- 
rents, undermining  large  masses,  which,  being  softened  by  the 
water,  slide  down  into  the  valleys. 

Two  landslips  occurred  in  Troy,  N.  Y.,  in  1836  and  1837, 
which  appear  to  have  resulted  from  the  action  of  springs  of  water 
in  fissures  of  clay  beds.  The  beds  of  clay  and  gravel  were  227 
feet  high.  A  spring  of  water  was  obstructed,  and  filled  up  a  fis- 
sure, and,  by  its  pressure,  forced  off  a  large  mass  of  clay  and 
earth,  the  weight  of  which  was  estimated  to  be  200,000  tons, 
which  slid  down  the  declivity,  carrying  every  thing  before  it,  to 
the  second  street  of  the  city,  a  distance  of  200  yards.  The 
slide  was  accompanied  by  torrents  of  mud  and  water.  Several 
buildings  were  buried  in  the  ruins,  and  some  persons  lost  their 
lives. 

A  few  years  since,  a  tract  of  land  at  Champlain,  Lower  Can- 
ada, consisting  of  207  acres,  resting  on  a  steep  slope,  suddenly 
slid  down  360  yards  into  the  Champlain  River,  and  dammed  it 
up  for  three  fourths  of  a  mile.  The  slide  produced  a  loud,  rum- 
bling noise,  and  filled  the  air  with  a  dense,  suffocating  vapor. 
One  individual  was  buried  to  his  neck  in  the  moving  mass,  but 
finally  escaped  without  injury. 

In  1826,  a  similar  slide  took  place  near  the  notch  in  the  White 
Mountains,  and  destroyed  a  whole  family. 

VI.  Glaciers. — The  history  of  glaciers  has,  within  a  few  years, 
excited  much  interest,  not  only  on  account  of  their  remarkable 
effects  and  mode  of  action,  but  of  their  applicability  on  a  grand 
scale  to  the  explanation  of  the  phenomena  of  drift. 

1.  Origin  of  Glaciers. — Under  the  equator,  a  perpendicular  as- 
cent of  three  miles  brings  us  to  regions  where  the  temperature 
of  the  air  is  below  the  freezing  point,  and  as  we  approach  the 
poles  this  point  is  reached  at  a  much  less  elevation,  until,  in  the 
latitude  of  65°  or  70°,  the  soil  is  frozen  most  of  the  year.  In 
most  countries  there  are  mountains  whose  tops  extend  far  above 
this  line  of  perpetual  congelation.  Their  tops,  therefore,  become 
the  repositories  of  eternal  frosts  and  snows.  When  we  ascend 
such  mountains  under  the  equator,  we  pass  through  all  the  cli- 
mates of  the  globe,  torrid,  temperate,  and  frigid.  In  temperate 
climates  there  will  be  a  broad  belt  where  the  snows  and  ice  will 
Mention  examples.  How  do  glaciers  originate  1 


30 


GLACIERS    OF    THE    ALPS. 


be  extended  down  a  considerable  distance  during  the  winter,  and 
retreat  much  higher  up  during  the  summer. 

Glaciers  and  mers  de  glace  (seas  of  ice)  originate  in  snow 
which  has  been  partially  melted  and  then  frozen.  The  lower 
part,  by  the  percolation  of  water,  is  converted  into  solid  ice. 
The  upper  part  is  more  granular.  Increasing  by  annual  layers 
of  enow,  the  glacier  is  stratified. 

Fig.  6. 


GLACIER    DU    LAUTER-AAR   (SWITZERLAND). 

In  the  higher  regions  of  the  Alps  there  are  extensive  table- 
lands, which  are  covered  with  thick  masses  of  ice,  through  which 
the  sharp  mountain  peaks  rise  to  a  yet  greater  height.  These 
icy  plains  are  called  mcrs  de  glace.  The  glaciers  extend  down 
the  valleys,  until  they  arrive  at  a  region  where  the  heat  arrests 
their  progress.  In  some  parts  of  the  Alps,  this  limit  is  met  at  an 
elevation  of  7000  feet.  But  some  of  the  glaciers  extend  down 
to  an  elevation  of  3000  feet.  Their  thickness  is  very  unequal,  in 
some  places  being  600  or  800  feet,  while  the  average  is  more  fre- 
quently 100  to  200  feet.  Some  are  ten  to  fifteen  miles  long,  with 
a  breadth  of  two  or  three  miles.  The  upper  surface  is  extremely 
uneven,  and  is  often  covered  with  needle-shaped  masses.  Fis 
Bures  frDm  20  to  100  feet  wide  are  common,  having  been  pro- 

What  is  said  of  their  thickness,  extent,  and  surface  in  the  Alps? 


MOTION    OF  GLACIERS. 


31 


duced  by  the  contraction  of  extreme  cold  in  the  winter,  and  en- 
larged by  the  melting  of  the  sides  in  the  summer.  The  slope  oi 
glaciers  is  usually  moderate.  That  of  Aar  descends  3000  feet 
in  fifteen  miles. 

2.  The  rate  of  motion  in  glaciers  is  very  slow.  Professoi 
Hughes,  in  1824,  built  a  house  on  the  glacier  of  the  Arvre,  which 
during  fifteen  years  descended  at  an  average  rate  of  eight  inches 
in  twenty-four  hours. 

Several  causes  co-operate  to  effect  the  motion  of  glaciers. 
Gravity  and  the  forms  of  the  valleys  determine  their  downward 
route.  Water,  freezing  in  the  pores  and  fissures  of  the  mass, 
expands  with  an  irresistible  force,  which  is  directed  by  the  sides 
of  the  valley  downward.  But  the  mass  is  not  a  perfectly  rigid 
solid  ;  it  is  flexible,  and  susceptible  of  motion  like  an  extremely 
viscid  fluid.  It  therefore  yields  to  the  pressure  from  above  of 
gravity  and  expansion,  and  descends,  in  some  seasons,  several 
miles  down  the  valley,  destroying  every  object  in  its  way. 

Ft?.  7. 


LOWER    PART   OF    THE    GLACIER   OF   THE    VIESCH 


The  retreat  of  a  glacier  consists  merely  in  the  melting  of  the 
lower  extremity,  which  varies  according  to  the  warmth  of  the 
A  literal  retrograde  motion  is  impossible. 


summers. 


AGENCY    OF    GLACIERS. 


UPPER    PART    OF   THE    GLACIER   OF    THE    VIESCH 


EFFECTS    OF    GLACIERS. 


33 


3  Effects  of  Glaciers. — In  their  progress  glaciers  crowd  along 
all  the  movable  materials.  The  accumulations  in  front  have  the 
form  of  rounded  hills,  and  are  called  terminal  moraines.  The 
accumulations  along  the  sides  are  long  ridges,  and  are  called 
lateral  moraines.  When  glaciers  descend  from  two  converging 
valleys  into  one,  they  unite,  and  the  union  of  the  adjacent  sides 
forms  a  medial  moraine,  which  extends  down  the  valley  in  the 
middle  of  the  double  glacier.  Fig.  6  shows  two  moraines  which 
unite  in  one.  Large  isolated  fragments  of  rocks  are  often  seen 
on  pedestals  of  ice  (as  in  Fig.  8),  that  have  been  protected  by 
these  rocks  from  the  melting  and  evaporation  which  have  re- 
moved the  general  surface.  The  small  stones  conduct  the  di- 
urnal heat  through  them,  so  that  the  icy  pedestals  are  not  formed 
beneath  them.  On  the  contrary,  the  melting  and  evaporation  of 
the  surface  expose  other  stones,  which  are  washed  away  by  tor- 
rents of  water  that  descend  upon  the  glacier  from  the  neighbor- 
ing hills. 

Generally  the  under  sur-  Fig' 9> 

face  is  thickly  studded  with 
angular  rocks,  pebbles,  and 
coarse  sand.  These  projec- 
ting fragments,  being  press- 
ed down  by  the  great  weight 
of  the  ice  on  the  rocks  over 
which  the  glacier  proceeds, 
make  grooves  and  scratch- 
es, while  the  finer  materials 
smooth  or  finely  striate  the 
surface.  As  the  glacier  re- 
tires or  advances,  new  striae 
are  formed,  which  slightly 
vary  in  direction,  although 
each  set  are  perfectly  par- 
allel to  each  other.  This 
is  due  to  the  fact  that  the  ROCKS  STRIATED  BY  GLACIERS. 

materials  are  firmly  frozen  into  the  ice.     Fig.  9  represents  a  por- 

What  are  moraines,  and  how  are  they  produced  ?  What  is  the  appearance 
of  the  surface  ?  Why  do  large  rocks  stand  on  pedestals  of  ice  ?  Why  do  not 
small  stones  also  ? 

B2 


34  EFFECTS    OF    GLACIERS. 

tion  of  a  rock  striated  by  the  Alpine  glaciers.  Sometimes  a  stone 
gets  loose  and  makes  in  the  rock  an  oblique  furrow  of  unequal 
depth.  The  loose  materials  are  crushed,  rounded,  and  ground 
over  the  surface,  until  most  of  them  are  reduced  to  sand  and  fine 
mud.  At  the  termination  of  the  glacier  there  are  conical  hills, 
which,  as  the  glacier  advances  during  some  seasons  further  than  at 
others,  aie  crowded  uppn  each  other,  and  present  an  appearance 
which  resembles  the  rounded  hills  along  the  margin  of  the  river 
valleys,  far  from  any  existing  glacial  agency.  The  rocks  on  the 
sides  of  the  glacier  are  striated  and  embossed  in  a  similar  man- 
ner with  those  at  the  bottom,  while  those  portions  of  the  mount- 
ain which  are  above  its  influence  present  a  rough  and  ragged 
appearance.  This  effect  is  seen  in  the  following  figure.  Em- 

Fig.  10. 


ROCKS    EMBOSSED    BY    GLACIERS    (ALPS,    S WITZKRLAM)). 

bossed  and  striated  rocks  occur  over  a  large  portion  of  the  north 
ern  hemisphere  as  the  result  of  glacial  action  during  a  former 
period  of  the  earth's  history. 

In  colder  countries  glaciers  descend  to  lower  levels.  "  In 
Chili,  which  has  the  same  latitude  as  the  Alps  in  Switzerland, 
we  have  glaciers  descending  to  the  sea ;  but  at  the  Alps  they 
cnly  descend  within  3000  feet  of  the  sea  level,  and  this,  too,  al- 
though the  Andes  are  only  7000  feet  high,  half  the  height  of  the 

What  effects  are  wrought  on  the  rocks  at  the  bottom  and  sides  of  the  gla- 
cier? Whore  do  glaciers  descend  to  the  sea? 


MARINE    AGENCIES.  35 

Alps  in  the  same  latitude.  The  reason  of  this  singular  phenom- 
enon is  that  to  which  I  have  alluded,  that  the  summer  heat  is 
less  intense  in  the  Alps.  In  Europe  we  have  to  go  to  latitude 
67  degrees  before  we  find  a  single  glacier  reaching  to  the  sea. 
But  in  the  southern  hemisphere,  in  latitude  46  degrees,  in  Chili, 
we  find  this  occurring  twenty-one  degrees  nearer  the  equator ; 
so  that  there  is  here  an  actual  generation  of  icebergs  in  a  region 
which  is  almost  the  limit  to  where  the  floating  icebergs  reach." 
— Lydl.  In  all  latitudes,  an  open  sea  terminates  glaciers,  by 
melting  and  breaking  off  the  parts  which  reach  the  water. 

It  will  be  noticed  that  large  quantities  of  matter  are  carried 
down  by  glaciers  from  higher  to  lower  levels.  Large  blocks  of 
Btone  are  borne  along  in  the  glacier,  and  large  hills  are  formed 
at  its  termination.  The  hills  are  mostly  very  finely-pulverized 
rock.  Much  of  this  is  taken  up  by  the  streams  of  water  and  car- 
ried onward  toward  the  ocean.  It  is  difficult  to  estimate  the 
quantity  of  matter  thus  transported  by  glaciers ;  but  when  we 
consider  the  great  extent  of  surface  acted  upon  not  only  in  the 
Alps  and  Andes,  but  in  all  high  northern  and  southern  latitudes* 
we  must  regard  them  as  highly  important  agents  in  modifying 
the  surface  of  the  earth. 

VII.  Avalanches. — Avalanches  are  masses  of  ice  and  snow, 
which  are  precipitated  down  the  steep  declivities  of  mountains. 
In  Switzerland  avalanches  are  very  frequently  precipitated  into 
the  valleys.  In  Chili  avalanches  of  ice  fall  into  the  sea,  and  float 
off  as  icebergs. 

SECTION  II.— MARINE  AGENCIES. 

The  materials  which  are  borne  along  by  livers,  if  not  deposit- 
ed along  their  course,  are  consequently  carried  into  lakes,  seaa, 
and  oceans,  and  distributed  in  sedimentary  strata  over  their  beds. 
We  are  now  to  glance  at  the  agencies  which  regulate  and  mod- 
ify this  distribution.  In  lakes,  especially  those  of  small  extent, 
the  modifying  agencies  are  slight,  and  the  strata  will  ordinarily 

What  general  effects  are  produced  by  glaciers?  What  aro  avalanches! 
What  becomes  of  the  materials  borne  down  by  rivers  ? 


36  ICEBERGS. 

constitute  basin-shaped  deposits.  But  in  oceans  and  seas  there 
are  several  powerful  causes  which  are  of  great  interest  not  only 
on  account  of  the  effects  which  they  are  actually  producing,  but 
because  the  effects  are  examples  of  agencies  which  have  in  for- 
mer epochs  acted  in  a  similar  manner  to  form  a  large  portion  of 
the  present  surface  of  continents.  They  are  icebergs,  waves, 
tides,  and  currents. 

I.  Agency  of  Icebergs. — Icebergs  are  masses  of  fresh-water  ice, 
which  are  seen  floating  on  the  ocean  or  stranded  on  shoals  both 
in  the  northern  and  southern  hemispheres,  and  with  few  excep- 
tions in  latitudes  above  40°. 

1.  Origin. — In  their  origin,  icebergs  are  glaciers  formed  in  the 
higher  latitudes  along  the  coasts  and  in  the  bays,  in  the  same 
manner  in  which  glaciers  are  formed  in  the  Alps.  The  new  Ant- 
arctic continent,  which  was  discovered  in  66°  south  latitude,  by 
the  American  exploring  expedition,  was  found  to  be  bounded  con- 
tinuously by  icy  cliffs  from  one  hundred  and  fifty  to  two  hundred 
feet  in  height,  without  any  appearance  of  rocks.  "  No  break  in 
this  icy  barrier  where  a  focit  could  be  set  on  the  rocks  was  ob- 
servable from  aloft."  A  long  range  of  icebergs  was  seen  strand- 
ed in  the  sea,  where  bottom  could  not  be  reached  with  a  line  of 
nine  hundred  feet.  The  margin  of  the  icy  barrier  was  only  here 
and  there  pierced  by  deep  bays,  but  otherwise  \vas  quite  uniform, 
A  few  floating  icebergs  were  seen  with  rocks  and  earth  on  them, 
on  one  of  which  a  landing  was  effected  and  some  geological  spec- 
imens were  obtained.  One  rock  was  five  or  six  feet  in  diameter. 
On  the  iceberg  was  a  pond  of  fresh  water  of  an  acre  in  extent. 
Captain  Wilkes  describes  the  icebergs  which  were  seen  near 
their  source  as  distinctly  stratified,  resulting  from  successive  de- 
posits of  snow,  which  were  supposed  to  fall  to  the  amount  of 
thirty  feet  per  year.  By  occasional  thaws  they  became  more 
compact,  aided  not  a  little  by  the  fogs,  which  on  one  occasion 
formed  one  fourth  of  an  inch  of  ice  on  the  rigging  in  a  few  hours. 

The  Astrolabe  (of  a  French  expedition)  "  skirted  for  sixty 

What  are  icebergs,  and  where  do  they  occur  ?  How  do  they  oiijiinat**  ? 
Give  examples  near  the  Antarctic  continent. 


ORIGIN    OF    ICEBERGS.  37 

miles  a  perfectly  vertical  wall  of  ice,  elevated  one  hundred  and 
twenty  to  one  hundred  and  thirty  feet  above  the  waves.  The 
surface  of  the  ice  was  perfectly  level.  Here  we  have  the  source 
of  the  enormous  level  icebergs." — Hayes. 

In  other  cases,  especially  in  latitudes  where  the  sun  has  suffi- 
cient power  in  summer  to  melt  most  of  the  snow,  icebergs  are 
formed  chiefly  in  narrow  valleys  at  the  head  of  inlets  of  the  sea, 
where  the  snow  is  sheltered  from  the  low  summer's  sun,  and  the 
water  flows  down  on  it  from  the  neighboring  hills.  Thus  in 
South  Georgia  are  formed  perpendicular  or  overhanging  cliffs  of 
ice  several  hundred  feet  high. 

In  Sandwich  Land,  an  intelligent  navigator  observed  that  "  the 
ice  made  from  the  tops  of  the  highest  hills  down  into  the  sea. 
In  one  place  in  particular,  the  sea  had  washed  in  under  the  ice 
as  far  as  we  could  see,  and  this  huge  body  of  ice,  four  or  five 
hundred  feet  in  height  on  its  face,  and  a  mile  or  two  in  length, 
hung,  not  touching  the  beach  by  four  or  five  feet,  except  at  tho 
sides  of  the  mountains  where  it  formed.  The  face  next  the  sea 
was  nearly  perpendicular.  *  *  In  Greenland  the  long  narrow 
bays  or  fiords,  like  broad  rivers,  run  far  up  amid  the  lofty  mount- 
ains or  table-lands  of  the  interior.  The  vast  plains  of  the  inte 
rior  abut  upon  these  fiords  ;  hence  the  greater  number  are  closed 
by  a  glacier,  close  to  which  the  water  has  a  depth  of  several  hund- 
red fathoms.  Several  of  the  inlets  are  now  completely  filled  up, 
and  at  others  the  ice  projects  far  out  into  the  waves,  forming  a 
considerable  promontory.' ' — Hayes. 

In  the  eastern  part  of  Iceland  is  a  region  of  3000  square  miles 
almost  entirely  covered  with  vast  mountains  of  ice. 

Undermined  by  the  waves  and  ruptured  «by  the  frost,  immense 
jnasses  are  occasionally  detached  into  the  sea,  producing  by  their 
fall  enormous  waves,  which  loosen  other  masses,  and  urge  on  ice- 
bergs which  have  stranded.  The  noise  made  by  the  fall  of  the 
enormous  masses  of  ice  is  compared  to  thunder,  and  by  the  first 
settlers  on  the  Shetland  Isles  was  mistaken  for  earthquakes 
Most  of  the  falling  masses,  however,  are  comparatively  small  frag- 
ments, and  no  one  has  seen  the  detachment  of  the  larger  ice  isl- 
ands. These  are  several  miles  in  extent ;  navigators  frequently 
mention  them  as  being  from  five  to  ten  miles  in  length.  Th% 

What  effect  have  waves  upon  ice  near  the  shore  ?     What  are  ice  islands  ? 


38 


MOTION    OF    ICEBERGS. 


French  exploring  expedition,  above  mentioned,  measured  several 
which  were  a  mile  in  breadth ;  and  one  was  13  miles  long,  with 
vertical  walls  100  feet  high.  It  must,  therefore,  have  been  600 
or  800  feet  thick.*  Another,  seen  by  the  same  expedition,  was 
225  feet  high,  which  would  give  a  depth  below  the  surface  of 
1200  to  1800  feet.  Capt.  Ross  saw  several  aground  in  Baffin's 
Bay,  in  water  which  was  1500  feet  deep. 

Fig.  11. 


ICEBERG   SEEN    BY    CAPTAIN    ROSS. 

2.  Motion. — The  motions  of  icebergs  are  of  great  importance, 
not  merely  for  the  effects  produced  at  the  present  time,  but  for 
their  bearing  on  the  theories  of  the  drift  deposits.  The  most 
ordinary  motion  is  a  uniform  slow  progress  from  higher  to  warm- 
er latitudes,  irrespective  of  wind  and  waves.  This  motion  is  the 

*  Ice  floats  with  one  ninth  of  its  bulk  above  the  surface.  Making  allowance 
ibr  any  want  of  compactness,  and  especially  for  a  greater  breadth  of  the  base, 
the  depth  of  an  iceberg  may  be  reckoned  at  between  five  and  eight  times  tho 
height. 

What  is  said  of  the  thickness  of  icebergs  ?  of  their  motion  ? 


MOTION    OF    ICEBERGS.  39 

effect  of  those  under  currents  with  which  their  enormous  depth 
in  the  water  brings  them  in  contact.  Immense  numbers  of  them 
are  from  this  cause  often  seen  to  the  east  of  Newfoundland.  Float- 
ing from  the  north,  they  at  length,  in  latitude  43°,  come  into  the 
warm  Gulf  Stream,  which  there  has  an  eastern  course.  Urged 
on  by  the  current  beneath,  they  float  across  the  Gulf  Stream,  and 
usually  disappear  before  they  reach  its  southern  side  in  latitude 
3.6°.  Some  of  them  get  aground  on  the  Grand  Banks  before  they 
reach  the  Gulf  Stream. 

One  of  the  most  extraordinary  examples  of  size  and  motion. 
was  an  iceberg  seen  by  the  British  steamer,  the  Acadia,  on  the 
16th  of  May,  1842,  among  a  hundred  others,  and  which  was  400 
to  500  feet  high,  and  consequently  about  3000  feet  deep  in  the 
water.  It  must,  therefore,  have  nearly  equaled,  from  the  base 
to  the  summit,  the  highest  peaks  of  the  Green  Mountains.  Hav- 
ing a  remarkable  resemblance  to  St.  Paul's  Cathedral  in  London, 
it  was  named  St.  Paul's.  But  the  most  extraordinary  part  of  the 
narrative  is,  that  "on  the  6th  of  June  the  same  object  was  seen, 
and  the  immediate  exclamation  on  board  was,  there  is  our  old 
friend  St.  Paul's.  In  the  interim  between  the  two  views,  the 
iceberg  had  drifted  about  70  miles."  This  slow  motion,  70 
miles  in  twenty-one  days,  is  worthy  of  notice.  The  maximum 
force  of  the  polar  current  off  Newfoundland  is  two  miles  per 
hour,  and,  although  liable  to  be  retarded,  it  can  hardly  be  sup- 
posed to  be  reduced  to  one  seventh  of  a  mile  per  hour  for  21 
clays.  It  is  not  improbable  that  this  enormous  iceberg  was  re 
tardecl  by  plowing  the  bottom  of  the  sea  in  some  parts  of  its 
course. 

In  the  southern  hemisphere,  currents  from  the  polar  regions, 
in  the  same  manner,  float  the  icebergs  into  warmer  latitudes,  oc- 
casionally as  far  as  the  latitude  of  the  Cape  of  Good  Hope. 

In  their  progress  into  regions  of  less  intense  cold,  the  structure 
of  icebergs  changes  ;  the  stratification  disappears,  and  the  whole 
becomes  a  compact  mass  of  translucent  blue  ice,  and  the  surface 
presents  all  conceivable  forms,  which  the  imagination  easily  con- 
verts into  a  city  with  its  spires,  domes,  and  battlements. 

Another  motion  is  that  of  a  violent  heaving  and  rolling  of  the 
mass  when  aground.  Captain  Couthuoy,  in  August,  1827,  saw 
one  stranded  on  the  Grand  Bank  in  about  500  feet  of  water 


40  WAVES THEIR    SIZE. 

around  which,  to  the  distance  of  one  fourth  of  a  mile,  the  water 
was  full  of  mud,  stirred  up  by  the  violent  rolling  of  the  mass. 

Icebergs  floating  into  warmer  water,  and  melting  more  rapid- 
ly on  some  parts  than  others,  sometimes  change  their  center  of 
gravity,  and  the  enormous  mass  is  seen  to  topple  over,  producing 
great  commotion  in  the  water. 

3.  Dissolution. — The  dissolution  of  icebergs  is  sometimes  effect- 
ed by  a  violent  explosion,  rending  the  whole  into  fragments,  which 
soon  disappear.     Several  cases  of  this  kind  are  recorded,  and  are 
supposed  to  be  owing  to  the  expansion  of  bodies  of  air  confined 
within  the  ice  at  a  temperature  much  below  the  freezing  point, 
and  when  the  temperature  of  the  ice  rises  up  to  this  point,  the  air 
must  expand  and  the  ice  explode.     But  the  ordinary  process  is 
that  of  melting  in  warmer  waters. 

4.  Effects. — It  is  obvious  that  the  foreign  materials,  rocks  and 
earth,  which  may  be  borne  along  with  them,  will  be  dropped  in 
their  path  on  the  bed  of  the  ocean.     It  is,  however,  rarely  that 
icebergs  at  a  great  distance  from  their  original  source  are  seen 
thus  loaded.     The  one  above  mentioned,  as  seen  by  Captain 
Couthuoy,  was  thus  loaded,  and  a  few  other  cases  are  recorded. 
But  they  are  rare,  and  many  navigators  have  seen  thousands  of 
icebergs  no  one  of  which  bore  along  any  foreign  materials.     On 
the  other  hand,  such  materials  have  often  been  seen  on  them  be- 
fore and  soon  after  they  were  detached.     In  many  cases,  a  mavss 
of  rocks  and  earth  may  be  a  nucleus  around  which  the  ice  has 
accumulated ;  yet,  since  these  materials  must  rest  on  some  base, 
they  can  not  occupy  the  interior  of  the  ice,  and  therefore  are  lost 
soon  after  the  icebergs  are  detached.     Any  materials  which  ad- 
here to  their  sides  will  be  dropped  near  their  source. 

Icebergs  often  are  stranded,  and,  being  urged  along  by  the  force 
of  currents,  or  turned  about  by  the  action  of  waves,  produce  im- 
portant effects  on  the  bottom  of  the  sea. 

II.  Waves.  1.  Size. — In  consequence  of  the  indefinite  and 
imaginative  descriptions  which  are  common  of  waves  running 
'•  mountains  high,"  those  who  are  not  familiar  with  the  open 

In  what  manner  do  icebergs  dissolve  ?     What  are  the  effects  of  icebergs  ? 


SIZE,  MOTION,  AND    EFFECTS    OF   WAVES.  4i 

ocean  seldom  have  correct  conceptions  of  them.  These  "  mount 
ains"  rarely  exceed  thirty  feet  in  height,  although  they  have 
been  observed  in  the  North  Atlantic  with  a  height  of  forty-five 
feet.  In  one  example  of  waves  on  a  scale  of  unusual  magnitude, 
the  height  of  their  summits  was,  for  the  most  part,  not  over  thir- 
ty feet  above  the  bottom  of  the  depressions,  and  the  highest  did 
not  exceed  thirty-five  feet.  Although  they  were  suddenly  raised 
by  a  storm,  which  had  been  immediately  preceded  by  another  at 
right  angles,  in  the  Gulf  Stream,  and  were,  of  course,  unusually 
short  and  narrow,  the  height  was  less  than  one  tenth  of  the  width. 
Enormous  as  are  these  masses,  which  may  be  half  a  mile  or  more 
in  length,  the  sublimity  of  such  a  scene  depends  more  on  their 
motion  than  on  their  magnitude. 

2.  The  motion  of  waves,  which,  as  is  well  known,  is  a  motion 
of  the  form  and  not  of  the  substance,  is  often  thirty  miles  per 
hour,  rapidly  rolling  past  the  fleetest  ships. 

But  since  the  motion  is  not  in  the  substance  of  the  water,  this 
agency  extends  but  to  a  moderate  depth,  and  geological  effects 
are  produced  only  when  waves  are  driven  on  shoals  and  coasts. 
Here,  on  account  of  the  resistance  of  the  bottom,  they  roll  up  with 
a  front  more  and  more  steep  until  it  becomes  perpendicular,  and 
at  length  fall  over  and  break  with  enormous  force,  dashing  up 
the  sides  of  rocky  cliffs,  or  rushing  far  up  the  shore  in  a  sheet  of 
foam. 

3.  Effects. — One  of  the  most  common  effects  is  the  wearing  of 
loose  stones,  originally  rough  and  angular,  into  smooth  oval  peb- 
bles.    On  a  sloping  shore  the  loose  stones  are  exposed  to  con- 
tinual friction  by  rolling  up  and  down,  and  usually  the  hardest 
stones  are  the  most  perfectly  rounded.     Where  the  rocks  consist 
of  limestone  with  a  small  proportion  of  flint,  the  pebbles  of  flint 
are  more  numerous  than  those  of  the  limestone,  most  of  the  latter 
having  been  worn  out  by  continual  friction.     The  form  of  peb- 
bles depends  somewhat  on  the  structure  of  the  rock.     Slates  fur- 
nish small  much-flattened  oval  forms,  producing  a  mass  of  gravel 

What  is  the  size  of  waves  ?     What  kind  of  motion  have  they  ?     Mention  the 
effects  of  waves  on  loose  stones. 


42  EFFECTS    OF    WAVES. 

or  shingle.  Some  steep  shores  of  hard  rocks  are  covered  deeply 
with  large  and  well-rounded  pebbles,  such  as  are  used  for  paving 
stones.  Storms  sometimes  pile  up  at  the  head  of  sandy  beaches, 
out  of  the  reach  of  ordinary  tides,  enormous  ridges  of  pebbles. 
An  example  may  be  seen  near  Boston,  at  Chelsea  beach,  between 
which  and  the  marshes  within  is  a  ridge  consisting  mostly  of  por- 
phyry pebbles  four  rods  wide,  ten  to  fifteen  feet  high,  and  two 
miles  long.  Stones  of  several  tons'  weight  are  also  moved  in 
storms  by  the  force  of  the  waves,  and  a  coast  is  modified  so  as  to 
be  recognized  only  in  its  outline,  the  minute  details  of  the  shore 
being  entirely  changed. 

On  coasts  which  are  fringed  with  cliffs  of  loose  materials,  the 
waves  undermine  the  cliffs  until  fragments  fall  down  an  easy  prey 
to  the  next  storm.  If  the  cliffs  are  composed  of  the  drift  de- 
posits, the  finer  materials  are  washed  away,  while  the  shore  at  its 
base  is  covered  with  large  bowlders.  But  if  the  cliffs  are  of  solid 
rock,  they  will  oppose  a  more  effectual  resistance.  Yet  solid  rock 
is  not  impregnable,  for  the  waves,  taking  up  loose  fragments,  use 
them  like  battering  rams  to  undermine  the  base  of  the  cliff,  while 
the  agency  of  frost  above  aids  in  the  work.  If  the  cliffs  be  of 
limestone  of  unequal  hardness  from  the  intermixture  of  silex,  pe- 
culiar and  remarkable  effects  are  produced.  The  silicious  frag- 
ments furnish  nearly  indestructible  pebbles,  which  wear  out  cav- 
ities, and  even  large  caverns  are  found  in  such  rocks  above  the 
present  sea  level.  Smooth  concave  surfaces  within  them  attest 
the  agency  by  which  they  were  formed. 

Examples  of  this  agency  are  to  be  found  wherever  high  lands 
are  in  contact  with  the  ocean.  The  numerous  indentations  of 
coasts  are  mainly  due  to  waves  and  currents.  The  following  cut, 
Fig.  12,  shows  the  undermining  action  of  the  waves  at  Nahant. 

At  this  place,  and  along  the  islands  of  Boston  harbor,  we  see  the 
harder  rocks  wearing  away  very  slowly,  while  the  softer  rocks 
and  loose  materials  are  rapidly  eroded,  so  as  to  render  sea  walls 

Describe  the  action  of  waves  on  loose  stones ;  on  cliffs  of  loose  materials  -, 
on  cliffs  of  solid  rock ;  on  rocks  of  unequal  hardness.  Give  examples  of  the 
action  of  waves  at  Nahant 


EFFECTS    OF    WAVES. 
Fig.  12. 


43 


PULPIT    ROCK,    KAHANT,    MASS. 

necessary  for  the  protection  of  the  harbor.  During  the  drift  pe- 
riod, this  harbor  was  probably  filled  up  with  loose  materials,  and 
it  has  been  re-excavated  by  the  joint  action  of  waves  and  tides. 

Remarkable  examples  of  the  agency  of  waves,  aided  more  or 
less  by  currents,  occur  along  the  shores  of  Long  Island,  parts  of 
which  have  had  a  much  greater  extent  since  the  commencement 
of  the  historical  period.  Rocks  which  were  once  covered  with 
soil  are  now  naked,  and  are  washed  by  the  waves.  The  coast 
from  Montauk  Point  to  Nepeague  beach,  a  distance  of  ten  miles, 
is  rapidly  wearing  away. 

At  Cape  May  (Del.),  the  sea  is  wearing  away  the  land,  in  some 
places,  at  the  average  rate  of  nine  feet  per  annum.  During  three 
years,  Sullivan's  Island  (S.  C.)  has  been  worn  away  one  quarter 
of  a  mile.  Much  of  the  eastern  coast  of  England  is  rapidly  crum- 
bling away,  and  many  towns  are  known  only  in  history,  their  sites 
now  forming  a  part  of  the  German  Ocean.  In  the  harbor  of  Sher 
ringham  there  was,  ten  years  since,  depth  sufficient  to  float  a 
frigate,  where,  forty-eight  years  before,  there  was  a  cliff  fifty  feet 

Give  examples  of  the  action  of  waves  at  Long  Island;  at  Cape  May  and 
Sullivan's  Island ;  in  England. 


44 


EFFECTS    OF    WAVES 


high  with  houses  on  it.     Some  Fig.  13. 

of  the  Shetland  Isles  have  been 
entirely  destroyed  by  the  action 
of  the  sea ;  others  are  now  un- 
dergoing the  process  of  destruc- 
tion, and  appear  like  fleets  of  ves- 
sels.    The  rocks  are  granite,  and 
the  accompanying  example,  Fig.   lss^ 
13,  taken  from  the  southern  part 
of  Hills  wickness,  Shetland,  gives  1 
a  good  idea  of  their  appearance. 

By  the  erosive  power  of  waves 
broad  channels  are  excavated.  In  the  thirteenth  century,  a  chan- 
nel was  worn  through  an  isthmus  in  the  northern  part  of  Holland, 
cutting  off  the  island  of  Wieringen  from  the  main  land.  The 
channel  is  now  13  miles  wide.  It  is  also  highly  probable  that 
the  English  Channel  was  produced  by  the  same  erosive  power. 

Waves  in  lakes  sometimes  exert  an  undermining  power  upon 
rocks,  especially  where  their  structure  is  jointed  so  as  to  expose 
them  to  atmospheric  agencies,  as  in  the  following  example  of  the 
cliffs  of  Cayuga  Lake,  N.  Y. 

Fig.  14. 


CLIFFS    OF    CAYUGA   LAKE,    N.    T. 


The  action  of  waves  and  currents,  however,  does  not  always 
carry  the  abraded  materials  out  to  sea.     In  some  cases  it  merely 

Describe  the  action  of  waves  on  the  Shetland  Isles.    What  examples  of  chan- 
nels worn  by  waves  ?     Of  undernv.nng  action  of  waves  in  lakes  ? 


OCEANIC    CURRENTS.  45 

transports  them  coastward,  and  forms  shoals,  flats,  and  sand-bars. 
In  other  cases,  the  matter  discharged  by  the  rivers  and  that  which 
is  worn  down  by  the  waves  is  thrown  back  upon  the  shores,  and, 
when  it  is  fine  sand,  gives  rise  to  what  are  termed  dunes  or  downs. 
These  are  formed  by  the  action  of  the  wind  upon  the  sand,  blow- 
ing it  inward,  and  often  destroying  the  fertility  of  extensive  tracts 
of  country. 

III.  Oceanic  Currents. — By  oceanic  currents  the  sea  is  power- 
fully aided  in  making  extensive  depredations  on  some  shores  and 
in  building  up  others. 

The  materials  which  are  brought  down  by  rivers  and  removed 
from  the  shore  by  waves  are  not  then  left  to  subside  at  once  to 
the  bottom  of  the  sea.  Oceanic  currents,  some  perpetual  and 
fixed  in  their  course,  and  others  intermittent  and  variable,  bear 
the  finer  sediment  into  the  deeper  part  of  the  ocean.  The  most 
remarkable  current  is  the  Gulf  Stream,  which  flows  past  the  east- 
ern coast  of  South  America,  bearing  the  sediment  of  the  Amazon 
to  the  north,  and  forming  vast  districts  of  lowland  between  that 
river  and  the  Oronoco ;  then  spreading  through  the  Caribbean 
Sea,  it  enters  the  Gulf  of  Mexico,  where,  being  pent  up,  it  rushes 
through  the  Straits  of  Florida  with  a  velocity  of  four  miles  per 
hour,  diminishing  to  three  miles  off  Cape  Hatteras,  whence  it 
takes  a  northeasterly  course  to  the  Banks  of  Newfoundland. 
There  it  is  met  by  another  current  from  Baffin's  Bay,  and  deflect- 
ed toward  Iceland,  Spitzbergen,  and  the  northern  parts  of  Scot- 
land. In  this  great  river  of  the  ocean  there  flow  about  90,000,000 
cubic  feet  of  water  per  minute,  or  2500  times  the  amount  dis- 
charged by  the  Mississippi.  The  polar  current  from  Baffin's  Bay 
is  divided  on  meeting  with  the  Gulf  Stream,  one,  portion  being 
supposed  to  run  under  the  latter  to  the  south,  and  the  other  to 
flow  on  the  surface  between  the  Gulf  Stream  and  the  coast  of 
North  America.  Another  current  of  great  size  flows  from  the 
Antarctic  Ocean  along  the  western  coast  of  South  America. 

What  are  the  effects  when  the  materials  are  transported  coastwise  ?  What 
are  downs  ?  What  are  the  effects  of  currents  on  the  shores  ?  on  the  liner  sedi- 
ment? Describe  the  Gulf  Stream.  What  is  said  of  other  currents  t 


46  AQUEOUS    AGENCIES. 

That  Arctic  01  Antarctic  currents  flow  beneath  the  surface  into 
the  equatorial  regions  of  the  Atlantic  is  proved  by  the  tempera- 
ture Df  the  Caribbean  Sea,  which  on  the  surface  is  80°,  but  at 
the  depth  of  240  fathoms  is  48°,  only  1°  warmer  than  at  a  corre- 
sponding depth  within  some  parts  of  the  Arctic  circle.  One  of 
the  under  currents  has  been  found  at  the  equator  200  miles  broad 
and  23°  colder  than  the  surface  water. 

These  great  currents  are  influenced  to  some  extent  by  long 
storms  and  prevailing  winds,  and  other  less  and  local  currents  are 
entirely  remodeled  by  storms. 

SECTION  III.— GENERAL  RESULTS  OF  AQUEOUS  AGENCIES. 

I.  Degradation. — The  general  tendency  of  the  aqueous  agen- 
cies, with  the  comparatively  unimportant  exception  of  springs, 
thus  appears  to  be  the  removal  of  soluble  and  movable  materials 
to  lower  levels.  These  levels  are  formed  first  at  the  base  of  preci- 
pices and  in  the  river  valleys. 

At  the  base  of  hills  or  cliffs  there  is  produced  a  talus  of  large 
angular  blocks,  a,  Fig.  15.  These  are  further  acted  upon  and 
broken  up,  as  at  Z>,  c,  d,  until  the  rains  or  tides  remove  the  finer 
portions  in  the  form  of  mud.  If  these  broken  materials  are  pre- 

Fig.  15.  ^j  Fig.  16. 


cipitated  into  streams  of  water,  the  finer  and  coarser  materials 
are  separated  and  arranged  in  successive  beds,  Fig.  16,  a,  b,  c,  d. 
A  portion  of  the  finer  materials  which  the  rivers  transport  is 
deposited  along  their  banks  and  at  their  mouths.  To  show  how 
the  mud  is  deposited  by  rivers,  let  a  a,  Fig.  17,  be  a  low  valley 
and  b  a  stream  of  water  over-  Fia  n 

flowing  its  banks  :   the   mud 
will  be    deposited    over   the 

space  a  a  in  horizontal  lay- 

•i  .    •> 

ers.     in  the  progress  of  time 


How  are  currents  modified?     What  is  the  general  tendency  of  aqueo\ii 
agencies  ?     Describe  the  deposits  at  the  base  of  cliffs  and  in  valleys. 


ORIGIN    OF    MARINE    FORMATIONS.  47 

the  bed  of  the  river  will  be  elevated,  as  at  6,  Fig.  18,  and  finally 
Fitr  ig  the  whole  valley  will  be  filled 

/  with  sediment,  or  dotted  with 
ponds  and  marshes  at  a  little 
distance  from  the  raised  banke 
of  the  stream. 

In  consequence,  however,  of  the  shifting  of  river  channels,  tht, 
only  permanent  resting-places  for  the  sediment  are  in  lakea  and 
the  ocean. 

II.  Salt  Lakes. — In  those  lakes  which  have  no  outlet,  thr.re  i; 
also  a  large  accumulation  of  soluble  materials.     Such  are  tho 
Salt  Lakes  in  Asia  and  in  Upper  Ca'iforrria.     Since  only  an  ex- 
tremely minute  proportion  of  salt  is  universally  diffused,  the  quan 
tity  in  rivers  is  not  usually  appreciable.     But  the  perpetual  sup- 
ply and  the  perpetual  concentration  by  evaporation  in  the  lakes 
tend  to  its  accumulation.  *  In  this  way  beds  of  salt  are  now  in 
the  process  of  formation. 

The  ocean,  also,  is  but  a  great  lake  without  an  outlet,  continu- 
ally receiving  the  discharge  of  rivers,  and  accumulating  the  salt 
by  evaporation.  A  minute  quantity  of  salt  is  returned  to  the 
land  by  evaporation,  but  this  is  probably  less  than  is  carried  off 
by  rivers.  Complete  restoration  is  effected  only  when  the  bed 
of  the  ocean  becomes  dry  land. 

III.  Basin-shaped  Deposits. —  The  deposits  in  lakes,  bays,  and 
harbors  are  more  or  less  basin-shaped.     The  sediment  is  in  lay- 
ers, which  conform  to  the  general  surface  of  the  bottom. 

IV.  Formations  of  Marine  Origin. — By  the  action  of  waves, 
tides,  and  currents,  a  large  portion  of  the  materials  which  are 
brought  down  by  rivers  is  removed  to  the  open  ocean,  where  it 
is  washed  up  to  form  new  shores  and  islands,  or  distributed  in 
vast  sheets  over  its  bed. 

So  numerous  and  extensive  are  the  agents  of  this  general  dis- 
tribution, that  the  ocean  may  be  regarded  not  as  a  great  lake, 
but  as  a  mass  of  broad  rivers  which  skirt  the  continents,  the  va- 

Where  is  the  final  resting-place  of  sediment?  What  is  said  of  salt  lakes? 
of  the  origin  of  salt  in  the  ocean?  of  basin -feiiaped  deposits?  of  marine  forma- 
tions? 


48  AaUEOUS    AGENCIES. 

rying  size  and  complexity  of  divided,  deflected,  upper  and  under 
currents,  present  to  the  geologist  a  vast  and  intricate  problem, 
whose  details  are  yet  to  be  solved.  If  the  fine  sediment  which 
comes  within  the  influence  of  these  currents  subsides  at  the  rate 
of  one  foot  per  hour,  it  will  be  carried  hundreds  or  thousands  of 
miles,  and  in  many  cases  by  upper  and  under  currents  in  different 
directions,  before  it  will  repose  on  the  bed  of  the  ocean.  There 
it  will  form  strata  which  are  destined  to  be  the  slate  rocks  of  the 
present  geological  epoch.  Off  the  coast  of  the  Southern  States, 
extensive  shoals  and  long  low  islands  occur,  which  are  separated 
from  the  main  land  by  large  bodies  of  water,  and  which  are  prob- 
ably the  products  of  oceanic  currents.  Long  Island  once  con- 
stituted several  islands,  which  have  been  united  into  one  by  the 
action  of  tides,  currents,  and  waves.  Off  Massachusetts  Bay,  far 
out  in  the  deep  sea,  but  west  of  the  (Julf  Stream,  are  dangerous 
shoals,  which  have  probably  been  formed  by  currents. 

Oceanic  currents  not  only  distribute  the  sediment  which  is  me 
clianically  suspended,  but  they  also  aid  the  waves  and  tides  in 
mingling  throughout  the  ocean,  with  great  uniformity,  its  saline 
ingredients,  whether  they  are  dissolved  primarily  by  its  own  wa- 
ters or  by  rivers. 

A  vast  quantity  of  organic  bodies,  as  we  shall  hereafter  show,  is 
enveloped  in  these  deposits  of  lakes  and  the  ocean.  Shell-fish  and 
many  other  aquatic  animals  live  and  die  in  them.  Multitudes  of 
terrestrial  animals  and  plants  are  earned  down  by  rivers  into  lakes 
and  the  ocean,  and  are  distributed  in  the  strata  of  rnud  and  sand. 

By  the  powers  of  cohesion  and  affinity,  which  are  aided  by  the 
pressure  of  superincumbent  waters,  and  in  some  regions  by  ig- 
neous agencies,  these  layers  of  sediment  are  consolidated.  Should 
the  sea  and  land  change  places,  these  new  strata  would  constitute 
a  formation  of  stratified  rocks,  resembling  those  of  the  present 
continents,  but,  unlike  those  of  former  geological  epochs,  they 
would  contain  abundantly  the  relics  of  man. 

What  is  the  effect  of  currents  on  the  distribution  of  the  saline  ingredients 
fA  the  ocean  ?  How  are  organic  bodies  entombed  ?  How  is  the  sediment 
fonsolidated  ?  How  may  a  new  formation  appear  ? 


EARTHaUAKES. THERMAL   SPRINGS,  49 


CHAPTER  II. 

IGNEOUS   AGENCIES. 

WE  have  seen  that  water  is  continually  corroding  the  conti- 
nents and  transporting  them  to  the  ocean.  Its  tendency  is  to 
level  down  all  inequalities  on  the  earth's  surface.  Heat,  on  the 
contrary,  exerts  its  power  in  an  opposite  direction.  It  tends  to 
elevate,  to  throw  into  ridges,  and  to  produce  irregularities  of  the 
surface.  By  these  opposing  forces  the  general  equilibrium  of 
sea  and  land  is  preserved. 

The  crust  of  the  earth  has  been  more  or  less  subjected  to  the 
action  of  heat  both  from  internal  and  from  external  sources.  The 
former  are  the  origin  of 'volcanic  action,  using  the  term  in  its  wider 
signification,  as  comprising  the  kindred  phenomena  of  volcanoes/ 
earthquakes,  and  thermal  springs. 

A  volcano  is  an  opening  in  the  earth,  out  of  which  ashes,  stones, 
and  melted  lava  are  ejected.  Around  the  opening  which  is  called 
the  crater,  a  mountain  usually  rises  in  the  form  of  a  truncated 
cone. 

Extinct  volcanoes  are  those  which  have  not  erupted  since  the 
commencement  of  the  historical  period ;  and  since  they  therefore 
oelong  to  the  history  of  antecedent  epochs,  the  consideration  of 
them  is  reserved  for  another  place. 

Active  volcanoes  are  those  which  have  been  known  to  erupt 
since  the  existence  of  man.  A  very  few  jof  these  are  in  constant 
action,  as  Stromboli  and  Kilauea,  but  the  greater  part  are  inter- 
mittent, with  intervals  of  action  varying  from  a  few  months  to 
many  centuries. 

Earthquakes  are  intimately  connected  with  volcanoes,  proceed- 
ing from  the  same  general  cause,  and  are  frequently  followed  by 

What  is  the  subject  of  chapter  ii.  ?  What  is  the  general  tendency  of  heat 
in  the  earth  ?  What  is  volcanic  action  ?  What  is  a  volcano  ?  What  are  ox 
tinct  volcanoes  ?  active  volcanoes  ?  earthquakes  ? 

c 


50  IGNEOUS    AGENCIES. 

an  eruption,  by  which  these  convulsive  throes  of  the  earth  are  re« 
lieved. 

Thermal  springs  belong  to  the  same  class  of  phenomena,  de 
riving  their  temperature  from  past  or  present  volcanic  fires,  with 
which  they  are  always  associated. 

The  facts  relating  to  earthquakes,  to  thermal  springs,  and  to 
volcanoes,  may  be  classified,  as  they  are  subaerial,  submarine,  or 
subterranean.  The  subaerial  phenomena  are  those  whicn  occur 
on  or  near  the  surface  of  the  dry  land ;  the  submarine  occur  in 
the  waters  of  the  ocean ;  by  the  subterranean,  we  mean  the  deep- 
seated  internal  igneous  action. 

SECTION  I— SUBAERIAL  IGNEOUS  AGENCY. 

I.  Volcanoes. — There  are  about  300  volcanoes,  of  which  one 
third  belong  to  America,  one  third  to  Oceanica,  and  the  remain- 
ing third  to  Europe,  Asia,  and  Africa. 

1.  Eruptions. — Usually  the  first  symptoms  of  an  eruption  are 
heard  in  rumbling  sounds,  which  seem  to  travel  along  for  a  great- 
er or  less  distance  in  the  depths  of  the  earth ;  they  are  seen  in 
the  increased  volumes  of  smoke  which  arise  from  the  crater,  and 
are  felt  in  tremulous  motions  of  the  earth, -which  assume  the  vio- 
lence of  earthquakes,  and  bring  in  their  train  the  horrors  that 
usually  accompany  these  convulsions.  Sulphurous  and  muriatic 
vapors  fill  the  air,  while  electric  agencies  display  their  vivid  cor- 
uscations, accompanied  with  heavy  peals  of  thunder.  Unusual 
signs  of  fright  are  manifested  by  the  brute  creation.  Showers 
of  stones  and  cinders  fall,  sometimes  in  immense  profusion,  and 
the  convulsions  of  the  earth  become  more  violent.  Masses  of 
rock  are  ejected  from  the  crater  with  tremendous  explosions,  un- 
til at  length  the  earthquakes  cease,  and  the  imprisoned  gases  and 
lava  find  vent  through  the  crater  and  sometimes  through  the  sides 
of  the  volcanic  mountain.  A  river  of  molten  rock  streams  down 
and  spreads  out  into  a  sea  of  fire.  Sometimes  its  course  is  slow 

What  are  thermal  springs  1  What  are  subaerial  igneous  phenomena  ?  sub 
marine?  subterranean?  What  is  the  number  of  volcano  eat  Describe  an 
ernption. 


VOLCANOES. VESUVIUS.  51 

sometimes  rapid.  Glaciers  may  be  encountered  and  melted,  and 
torrents  of  boiling  water  and  mud  poured  down.  Showers  of 
cinders  again  fall,  and  announce  the  termination  of  the  eruption 
to  be  at  hand.  The  flames,  explosions,  and  ejections  of  rocks  and 
stones  become  less  violent,  and  finally  nothing  but  vapors  and 
smoke  escape  from  the  crater. 

A  few  examples  of  eruptions  will  serve  to  illustrate  the  kind 
and  amount  of  changes  which  volcanoes  are  now  effecting,  and 
will  furnish  the  data  by  which  to  account  for  changes  which 
must  have  been  wrought  in  the  crust  of  the  earth  during  the  ear- 
lier  periods  of  its  history. 

2.  Vesuvius. — Before  the  Christian  era,  Vesuvius  was  in  a  state 
of  inactivity.  History  had  no  records  of  its  eruptions,  and  a  nat- 
uralist only,  as  he  observed  the  volcanic  nature  of  the  rocks, 
would  have  suspected  its  real  character.  Its  energies  found  vent 
in  the  neighboring  isles  of  Ischia  and  Procida,  which  were  shaken 
by  terrific  convulsions  and  desolated  by  eruptions.  But  Vesu- 
vius itself  was  silent ;  and  although  Strabo  perceived  its  volcanic 
character,  Pliny  omitted  it  in  his  list  of  active  volcanoes.  In  the 
cone  were  the  remains  of  an  ancient  crater  which  was  nearly  fill- 
ed up,  and  was  covered  on  its  interior  with  wild  vines.  At  the 
bottom  was  a  sterile  plain,  on  which  Spartacus  once  encamped 
with  his  army  of  10,000  gladiators,  whose  descent  was  a  more 
disastrous  eruption  than  the  fiery  floods  of  later  years.  The 
mountain  was  flanked  with  fruitful  fields  in  a  high  state  of  culti- 
vation, and  at  its  base  were  the  luxurious  and  populous  cities  of 
Herculaneum  and  Pompeii. 

In  A.D.  63,  Vesuvius  gave  signs  of  awakening  from  its  repose 
of  unknown  ages.  From  that  year  to  A.D.  79,  shocks  were  fre- 
quent, and  at  length  became  more  violent,  when  a  terrific  erup- 
tion took  place,  and  buried  the  cities  above  mentioned.  Since 
that  time  its^  eruptions  have  been  numerous,  but  those  of  1631 
and  1822  were  most  remarkable.  In  1631  a  stream  of  lava  con- 
sumed Resina,  which  had  been  built  over  *he  site  of  Herculane- 
um, and  floods  of  mud  were  poured  down  with  terrible  devasta- 

What  was  the  condition  of  Vesuvius  before  the  Christian  era?  Give  tha 
subsequent  history  of  Vesuvius 


52 


IGNEOUS    AGENCIES. 


tion.  These  floods  originated  in  heavy  rains,  which  are  often 
produced  by  volcanic  action,  and  which  wash  down  the  cinders 
and  dust  until  they  assume  the  consistency  of  mud.  Fig.  19  rep- 
resents the  appearance  of  an  eruption  of  Vesuvius  in  1784,  by 
which  Torre  del  Grecco  was  overwhelmed,  and  400  persons  were 
destroyed. 

Fig.  19. 


VIEW    OP    VESUVIUS,    1784. 

For  some  time  previous  to  1822  the  crater  had  been  gradually 
filling  up,  when  it  was  blown  out,  with  awful  explosions,  to  the 
depth  of  2000  feet,  and  more  than  800  feet  of  the  top  were  blown 
off.  Since  this  time  eruptions  have  been  frequent,  the  most  re- 
markable of  which  occurred  m  1849  and  1850. 

3.  JEtna. — JEtna  has  been  observed  from  the  remotest  antiqui- 
ty. It  is  situated  on  the  island  of  Sicily,  and  is  about  90  miles 
in  circumference  and  nearly  11,000  feet  high  (Fig.  20).  During 
the  epoch  of  the  eruptions  of  Vesuvius  above  described  ^tna 
was  occasionally  active. 

In  1669  an  immense  quantity  of  the  lava  overwhelmed  fouiteen 
towns  and  villages  before  reaching  Catania.  Although  the  wall-; 

Describe  .Etna ;  the  eruption  of  1669 ;  of  1811  and  1819. 


.ETNA.  53 

Fig.  20. 


VIEW    OF    JETNA,    LOOKING    UP    FROM    THE    VAL    DEL    BOVK. 

of  this  city  were  60  feet  high,  the  lava  accumulated  until  it  gained 
the  top,  and  then  poured  over  in  a  fiery  cascade  and  destroyed  a 
portion  of  the  city.  The  current  continued  15  miles  further, 
when  it  entered  the  sea  with  a  depth  of  40  feet.  The  progress 
of  this  current  had  been  so  slow  tbfit  the  surface  had  time  to  cool, 
so  that  it  advanced  by  breaking  through  its  walls  of  crust.  Since 
the  commencement  of  the  present  century,  there  have  been  sev- 
eral eruptions  through  the  sides  of  the  mountain.  In  1811,  seven 
openings  were  formed,  each  at  a  lower  level  successively.  In 
1819,  three  out  of  five  such  openings  united  in  one,  and  poured 
an  enormous  torrent  into  the  "Val  del  Bove."  Arriving  at  a 
precipice,  it  poured  over  in  a  cataract  of  liquid  rock,  which,  cool- 
ing in  its  descent,  dashed  against  the  bottom  with  an  inconceiva- 
ble crash.  This  current  continued  to  flow  for  nine  months,  when 
it  was  found  to  move  at  the  rate  of  less  than  five  rods  per  day.* 

*  A  late  traveler  gives  the  following  description  of  an  eruption  of  ^Etna  seen 
by  night : 

"  It  was  about  half  past  ten  when  we  reached  the  foot  of  the  craters,  which 
were  both  tremendously  agitated  ;  the  great  vent  threw  up  immense  columns 
of  fire,  mingled  with  the  blackest  smoke  and  sand.  Each  explosion  of  fire 
was  preceded  by  a  bellowing  of  thunder  in  the  mountain.  The  explosions 
followed  each  other  so  rapidly  that  we  could  not  count  three  seconds  between 
them.  The  stones  which  were  emitted  were  fourteen  seconds  in  falling  back 
to  the  crater;  consequently,  there  were  always  five  or  six  explosions — some- 
times more  than  twenty — in  the  air  at  once.  These  stones  were  thrown  up 
in  the  shape  of  a  wide-spreading  sheaf,  producing  the  most  magnificent  effect 
imaginable.  The  smallest  stones  appeared  to  be  of  the  size  of  cannon-balls ; 
the  greater  were  like  bomb-shells;  but  others  were  pieces  of  rock  five  or  six 
cubic  feet,  in  size,  and  some  of  the  most  enormous  dimensions ;  the  latter  gen- 
erally fell  on  the  ridge  of  the  crater  and  rolled  down  its  sides,  splitting  into 


54 


IGNEOUS    AGENCIES. 


Fig.  21. 


4.  In  Iceland  have  occurred  some  of  the  most  extensive  erup- 
tions on  record.  Most  of  this  island,  which  is  300  miles  long  and 
150  broad,  is  covered  with  volcanoes  and  vast  regions  of  lava, 
which  is  broken  into  ragged  and  pointed  rocks,  or  cleft  by  yawn- 
ing chasms  of  many  miles  in  length  and  of  unseen  depth.  Oth- 
er parts  of  the  island  are  filled  with  innumerable  springs  spout- 
ing forth  torrents  of  boiling  water,  or  with  immense  mountains 
of  ice. 

The  convulsions  of  1783  appear  to  have  been  most  violent,  and 
on  a  scale  of  extraordinary  magnitude.  In  an  eruption  of  Skap- 
tar  Jokul,  two  streams  of  lava  flowed  off  in  opposite  directions, 
of  which  one  was  40  miles  long  and  7  broad,  and  the  other  was 
50  miles  long  and  12  broad,  both  containing  70,000,000,000  cu- 
bic yards.  At  least  1300  human  beings  lost  their  lives  ;  and  not 
less  than  20,000  horses,  7000  horned  cattle,  and  130,000  sheep 
were  destroyed. 

5.  On  Hawaii  (Sand 
wich  Islands),  Fig.  21,  is 
an  ever-active  volcano,  Ki- 
lauea,  of  unusual  form  and 
situation.  "  The  whole  sur- 
face of  the  island  pertains 
to  the  slopes  of  three  lofty 
volcanic  summits,  Mount 
Loa,  constituting  the  south- 
ern portion,  13,760  feet  in 
height;  Mount  Kea,  long 
extinct,  covering  the  north- 
fragments  as  they  struck  against  the  hard  and  cutting  masses  of  cold  lava 
The  smoke  emitted  by  the  smaller  cone  was  white,  and  its  appearance  incon- 
ceivably grand  and  beautiful;  but  the  other  crater,  though  less  active,  was 
much  more  terrible ;  and  the  thick  blackness  of  its  gigantic  volumes  of  smoke 
partly  concealed  the  fire  which  it  vomited.  Occasionally  both  burst  forth  at 
the  same  instant  and  with  the  most  tremendous  fury,  sometimes  mingling  their 
ejected  stones. 

"  If  any  person  could  accurately  fancy  the  effect  of  500,000  sky-rockets 
darting  up  at  once  to  a  height  of  three  or  four  thousand  feet,  and  then  falling 
back  in  the  shape  of  red-hot  balls,  shells,  and  large  rocks  of  fire,  he  might, 
have  an  idea  of  a  single  explosion  of  this  burning  mountain ;  but  it  is  doubt- 
ful whether  any  imagination  can  conceive  the  effect  of  one  hundred  of  such 
explosions  in  the  space  of  five  minutes,  or  of  twelve  hundred  or  more  in  the 
course  of  an  hour/  as  we  saw  them !" — Mantell. 


Describe  Iceland;  the  eruption  of  1783.     What  is  said  of  Hawaii  I 


KILAUEA.  55 

ern  portion,  13,950  feet  in  height;   and  Hualalai,  toward  the 
western  shores,  estimated  at  10,000  feet." — Dana. 

The  crater  of  Kilauea,  Fig.  22,  is  not  in  a  truncated  cone  of  a 

Fig.  22, 


CRATER   OF    KILAUEA. 

mountain,  but  in  an  upland  country,  near  the  base  of  Mount  Loa. 
The  crater  is  an  immense  chasm,  in  the  middle  of  a  plain,  which 
is  surrounded  by  a  precipice  from  200  to  400  feet  high,  and  is 
15  miles  in  circumference ;  or  rather  this  plain  is  itself  a  chasm, 
and  the  crater  is  a  chasm  within  a  chasm.  Mr.  Stewart,  formerly 
missionary  at  these  islands,  gives  an  interesting  account  of  its  ap- 
pearance : 

"  Standing  at  an  elevation  of  1500  feet,  we  looked  into  the  horrid  gulf,  not 
less  than  eight  miles  in  circumference,  directly  beneath  us.  The  hideous 
immensity  itself,  independent  of  the  many  frightful  images  embraced  in  it, 
almost  caused  an  involuntary  closing  of  the  eyes  against  it.  But  to  the  sight 
is  added  the  effect  of  the  various  unnatural  and  frightful  noises,  the  every 
agonized  struggling  of  the  mighty  action  within.  This  gulf  contains  50  or  60 
conical  craters,  many  of  which  are  in  constant  action.  About  half  way  down 
the  perpendicular  side  of  the  chasm  is  a  ledge  or  piazza  of  lava  from  a  few 
feet  to  several  yards  in  width,  which  extends  all  around.  Below  this,  all  was 
of  a  dismal  black  color,  except  two  or  three  of  the  conical  craters  at  the  bot- 
tom, which  were  covered  with  sulphur  of  various  shades  of  yellow  and  green. 
The  cliffs  above  the  piazza  were  red  on  the  north  and  west  sides;  on  the  east 
the  bank  was  less  precipitous,  and  consisted  of  entire  banks  of  sulphur  of  a 
delicate  and  bright  yellow. 

"  As  the  darkness  of  the  night  gathered  around  us,  fire  after  fire  began  to 
glimmer  on  the  eye,  appearing  in  rapid  succession.  Two  or  three  small  cra- 
ters were  in  full  actionj  every  moment  casting  out  stones,  ashes,  and  lava, 
with  heavy  detonations,  while  the  flames  glared  over  the  surrounding  obscu- 

What  is  said  of  the  crater  of  Kilauea  ? 


56  VOLCANOES. 

rity,  richly  illuminating  the  more  distant  volumes  of  smoke.  The  great  seal 
of  action,  however,  seemed  to  be  in  the  southern  and  western  end ,  where  an 
exhibition  of  ever-varying  fire-works  was  presented.  Rivers  of  fire  were 
seen  rolling  in  splendid  coruscations  among  the  laboring  craters.  During  the 
second  night,'  the  noises  were  redoubled,  rolling  from  one  end  of  the  vast 
chasm  to  the  other  with  inconceivable  velocity,  and  the  flames  burst  from  a 
large  cone,  which  in  the  morning  appeared  to  have  been  long  inactive.  Red- 
hot  stones,  cinders,  and  ashes  were  propelled  to  an  immense  height,  and  soon 
the  lava  boiled  over  in  two  curved  streams  glittering  with  indescribable  brill 
iancy. 

"  A  whole  lake  of  fire  opened  in  a  more  distant  part,  two  miles  in  circum 
feren^e.  Its  surface  had  all  the  agitation  of  an  ocean ;  billow  after  billow 
tossed  its  monstrous  bosom  in  the  air,  and  occasionally  met  with  such  violent 
concussion  as  to  dash  the  fiery  spray  40  or  50  feet  high.  This  spray  is  blown 
out  by  the  winds  into  delicate  threads,  as  melted  glass  may  be  drawn  out,  and 
accumulates  on  the  sides  in  masses  which  resemble  bunches  of  tow." 

An  eruption,  which  had  its  source  in  this  volcano,  in  June,  1840, 
was  one  of  the  most  extraordinary  of  modern  times.  It  has  been 
described  by  Mr.  Coan,  an  American  missionary  in  the  Sandwich 
Islands,  who,  soon  after  the  eruption,  discovered  the  place  where 
the  current  broke  forth,  and  traced  it  to  the  sea.  We  give  his 
narrative  somewhat  abridged,  as  furnishing  one  of  the  most  in- 
structive examples  of  this  class  of  geological  agencies  : 

"  For  several  years  past  the  great  crater  of  Kilauea  has  been  rapidly  filling 
up.  The  great  basin  below  the  black  ledge  has  been  computed  to  be  from 
three  hundred  to  five  hundred  feet  deep.  Silent  eruptions  had  occurred  at 
intervals,  until  the  black  ledge  was  repeatedly  overflowed,  each  forming  a 
new  layer  from  two  feet  thick  and  upward,  until  the  whole  area  of  the  cra- 
ter was  filled  up,  at  least  fifty  feet  above  the  original  black  ledge.  This  pro- 
cess of  filling  up  continued  till  the  latter  part  of  May,  1840,  when,  as  many 
natives  testify,  the  whole  area  of  the  crater  became  one  entire  sea  of  igniflu- 
ous  matter,  raging  like  the  ocean  when  lashed  into  fury  by  a  tempest.  For 
several  days  the  fires  raged  with  fearful  intensity,  exhibiting  a  scene  awfully 
terrific.  The  infuriated  waves  sent  up  infernal  sounds,  and  dashed  with  such 
maddening  energy  against  the  sides  of  the  awful  caldron  as  to  shake  the  solid 
earth  above,  and  to  detach  huge  masses  of  overhanging  rocks,  which,  leaving 
their  ancient  beds,  plunged  into  the  fiery  gulf  below.  Every  thing  within  the 
caldron  is  new.  Not  a  particle  of  the  lava  remains  as  it  was  when  I  last  vis- 
ited it.  Ah1  has  been  melted  down  and  recast.  The  whole  appears  like  a 
raging  sea,  whose  waves  have  been  suddenly  solidified  while  in  the  most  vio- 
lent agitation. 

"  On  the  30th  of  May,  the  people  of  Puna  observed  the  appearance  of  smoke 
and  fire  in  the  interior,  a  mountainous  and  desolate  region  of  that  district. 
Thinking  that  the  fire  might  be  the  burning  of  some  jungle,  they  took  little 
notice  of  it  until  the  next  day,  when  the  sudden  and  grand  exhibitions  of  fire 
left  them  no  room  to  doubt  the  cause  of  the  phenomenon.  The  fire  augment. 
ed  during  the  day  and  night,  but  it  did  not  seem  to  flow  off  rapidly  in  any 
direction.  All  were  in  consternation,  as  it  was  expected  that  the  molten  flood 
would  pour  itself  down  from  its  height  of  four  thousand  feet  to  the  coast.  On 
Monday,  June  1st,  the  stream  began  to  flow  off  in  a  northeasterly  direction 
(from  »,  Fig-  21);  and  on  June  3d,  at  evening,  the  liver  reached  the  sea  (at 


KILAUEA.  5? 

Nanawale,  which  it  destroyed),  having  averaged  about  half  a  mile  an  hour  iu 
its  progress. 

"  The  source  of  the  eruption  »  in  a  forest,  and  iu  the  bottom  of  an  ancient 
wooded  crater  (a,  Fig.  21,  p.  54),  about  four  hundred  feet  deep,  and  prob. 
ably  eight  miles  east  from  Kilauea.  From  Kilauea  to  this  place  the  lava  flows 
in  a  subterranean  gallery,  probably  at  the  depth  of  a  thousand  feet,  but  its 
course  can  be  distinctly  traced  all  the  way  by  the  rending  of  the  crust  of  the 
earth  into  innumerable  fissures,  and  by  the  emission  of  smoke,  steam,  and 
gases.  The  eruption  in  this  old  crater  is  small,  and  from  this  place  the  stream 
disappears  again  for  the  distance  of  a  mile  or  two,  when  the  lava  again  gushes 
up  and  spreads  7>ver  an  area  of  about  fifty  acres  (c).  Again  it  passes  under 
grou:id  for  a  few  miles,  when  it  reappears  in  another  old  wooded  crater  (w»), 
consuming  the  forests,  and  partly  filling  up  the  basin.  Once  more  it  disap- 
pears, and,  flowing  in  a  subterranean  channel,  cracks  and  breaks  the  earth, 
opening  fissures  from  six  inches  to  ten  or  twelve  feet  in  width,  and  sometimes 
splitting  the  trunk  of  a  tree  so  exactly  that  its  legs  stand  astride  at  the  fissure. 
After  flowing  under  ground  several  miles,  it  again  broke  out,  like  an  over- 
whelming flood  (re),  and,  sweeping  forest,  hamlet,  plantation,  and  every  thing 
before  it,  rolled  down  with  resistless  energy  to  the  sea,  where,  leaping  a  prec- 
ipice of  forty  or  fifty  feet,  it  poured  itself  in  one  vast  cataract  of  fire  into  the 
deep  below,  with  loud  detonations,  fearful  hissings,  and  a  thousand  unearthly 
sounds.  Imagine  to  yourself  a  river  of  fused  minerals,  of  the  breadth  of  Niag- 
ara, and  of  a  gory  red,  falling,  in  one  emblazoned  sheet,  one  raging  torrent, 
into  the  ocean !  The  atmosphere  in  all  directions  was  filled  with  ashes,  spray, 
gases,  etc.,  while  the  burning  lava,  as  it  fell  into  the  water,  was  shivered  into 
millions  of  minute  particles,  and,  being  thrown  back  into  the  air,  fell  in  show- 
ers of  sand  on  all  the  surrounding  country.  The  coast  was  extended  into  the 
sea  for  a  quarter  of  a  mile,  and  a  sand-beach  and  a  new  cape  were  formed. 
Three  hills  of  scoria  and  sand  were  also  formed  in  the  sea,  the  lowest  about 
two  hundred,  and  the  highest  about  three  hundred  feet  high. 

"  For  three  weeks  this  terrific  river  continued  to  disgorge  itself  into  the  sea 
with  little  abatement.  Multitudes  of  fishes  were  killed,  and  the  waters  of  the 
ocean  were  heated  for  twenty  miles  along  the  coast.  The  breadth  of  the 
stream,  where  it  fell  into  the  sea,  is  about  half  a  mile,  but  inland  it  varies  from 
one  to  four  or  five  miles  in  width,  conforming  itself,  like  a  river,  to  the  face  of 
the  country  over  which  it  flowed. 

"  The  depth  of  the  stream  probably  varies  from  ten  to  two  hundred  feet,  ac- 
cording to  the  inequalities  of  the  surface  over  which  it  passed.  During  the 
flow,  night  was  converted  into  day  on  all  eastern  Hawaii.  The  light  rose  and 
spread  like  the  morning  upon  the  mountains,  and  its  glare  was  seen  on  the  op- 
posite side  of  the  island.  It  was  also  distinctly  visible  for  more  than  one 
hundred  miles  at  sea,  and  at  the  distance  of  forty  miles  fine  print  could  be  read 
at  midnight. 

"  The  whole  course  of  the  stream  from  Kilauea  to  the  sea  is  about  40  miles. 
Its  mouth  is  about  25  miles  from  Hilo  station.  The  ground  over  which  it 
flowed  descends  at  the  rate  of  one  hundred  feet  to  the  mile.  The  crust  is  now 
cooled,  and  may  be  traversed  with  ease,  although  scalding  steam,  pungent 
gases,  and  smoke  are  still  emitted  in  many  places. 

"  Hills  have  been  melted  down  like  wax;  various  and  deep  valleys  have 
been  illled  ;  and  majestic  forests  have  disappeared  like  a  feather  in  the  flames. 
In  some  places  the  molten  stream  parted  and  flowed  in  separate  channels  for 
a  great  distance,  and  then,  reuniting,  formed  islands  of  various  sizes,  from  ona 
to  fifty  acres,  with  trees  still  standing,  but  seared  and  blighted  by  the  intense 
heat.  On  the  outer  edges  of  the  lava,  where  the  stream  was  more  shallow, 
*nd  the  heat  less  vehement,  and  where,  of  course,  the  liquid  mass  cooled  soon- 

C2 


58  IGNEOUS    AGENCIES. 

est,  the  trees  were  mowed  down  like  grass  before  the  scythe,  and  left  char- 
red, smouldering-,  and  only  half  consumed,  ^s  the  lava  flowed  around  tho 
trunks  of  large  trees  on  the  outskirts  of  the  stream,  the  melted  maBs  stiffened 
and  consolidated  before  the  trunk  was  consumed,  and  when  this  was  effected, 
the  top  of  the  tree  fell,  and  lay  unconsutned  on  the  crust,  while  the  hole 
which  marked  the  place  of  the  trunk  remains  almost  as  smooth  and  perfect  as 
the  caliber  of  a  cannon.  These  holes  are  innumerable,  and  measure  from  ten 
to  forty  feet  deep,  but  they  are  in  the  more  shallow  parts  of  the  lava,  the  trees 
being  entirely  consumed  where  it  was  deeper.  During  the  flow  of  this  erup- 
tion, the  great  crater  of  Kilauea  sunk  about  three  hundred  feet,  and  her  fires 
became  nearly  extinct,  one  lake  only  out  of  many  being  left  active  in  this 
mighty  caldron.  This,  with  other  facts  which  have  been  named,  demonstrates 
that  the  eruption  was  the  disgorgernent  of  the  fires  of  Kilauea.  The  open  lake 
in  the  old  crater  is  at  present  intensely  active,  and  the  fires  are  increasing,  as  is 
evident  from  the  glare  visible  at  our  station,  and  from  the  testimony  of  visitors. 

"  While  the  stream  was  flowing,  it  might  be  approached  within  a  few  yards 
on  the  windward  side,  while  at  the  leeward  ho  one  could  live  within  the  dis- 
tance of  many  miles,  on  account  of  the  smoke,  the  impregnation  of  the  atmos- 
phere with  pungent  and  deadly  gases,  and  the  fiery  showers  which  were  con- 
stantly des6endiug  and  destroying  vegetable  life.  During  the  progress  of  the 
descending  stream,  it  would  often  fall  into  some  fissure,  and  forcing  itself  into 
apertures  and  under  massive  rocks,  and  even  hillocks  and  extended  plats  of 
ground,  and  lifting  them  from  their  ancient  beds,  bear  them  with  all  their  su- 
perincumbent mass  of  soil,  trees,  etc.,  on  its  viscous  and  livid  bosom,  like  a 
raft  on  the  water.  When  the  fused  mass  was  sluggish,  it  had  a  gory  appear 
ance,  like  clotted  blood  mingled  and  thrown  into  violent  agitation. 

"  Sometimes  the  flowing  lava  would  find  a  subterranean  gallery,  diverging 
at  right  angles  from  the  main  channel,  and,  pressing  into  it,  would  flow  off  un- 
observed, till  meeting  with  some  obstruction  in  its  dark  passage,  when,  by  its 
expansive  force,  it  would  raise  the  crust  of  the  earth  into  a  dome-like  hill  of 
fifteen  or  twenty  feet  in  height,  and  then,  bursting  this  shell,  pour  itself  out  in 
a  fiery  torrent  around." — Coan,  Sept.  25,  1840. 

In  this  eruption  the  quantity  of  matter  which  was  ejected 
amounted  to  6,000,000,000  cubic  feet.  The  old  crater  of  Kilau- 
ea lost  15,400,000,000  cubic  feet  of  its  contents,  the  greater  part 
of  which  therefore  must  have  been  drawn  off  into  subterranean 
fissures. 

6.  Another  illustration  we  quote  from  Lyell's  Principles  of 
Geology : 

"  In  April,  1815,  one  of  the  most  frightful  eruptions  recorded 
in  history  occurred  in  the  mountain  Tomboro,  in  the  island  of 
Sumbawa.  It  began  on  the  5th  of  April,  and  was  most  violent 
on  the  llth  and  12th,  and  did  not  entirely  cease  till  July.  The 
sound  of  the  explosions  was  heard  in  Sumatra,  at  the  distance  of 
970  geographical  miles  in  a  direct  line,  and  at  Ternate,  in  an  op- 
posite direction,  at  the  distance  of  720  miles.  Out  of  a  popula- 
tion of  twelve  thousand,  only  twenty-six  individuals  survived  on 

What  is  said  of  the  quantity  of  lava  lost  by  Kilauea  ?  Describe  the  eruption 
of  Tomboro. 


CHARACTERS    OF   LAVA.  59 

the  island.  Violent  whirlwinds  carried  up  men,  horses,  cattle, 
and  whatever  else  came  within  their  influence,  into  the  air ;  tore 
up  the  largest  trees  by  their  roots,  and  covered  the  whole  sea 
with  floating  timber.  Great  tracts  of  land  were  covered  with 
lava,  several  streams  of  which,  issuing  from  the  crater  of  the  Tom- 
boro  Mountains,  reached  the  sea.  So  heavy  was  the  fall  of  ashes, 
that  they  broke  into  the  president's  house  at  Birna,  forty  miles 
east  of  the  volcano,  and  rendered  it,  as  well  as  many  other  dwell- 
ings in  town,  uninhabitable.  On  the  side  of  Java,  the  ashes  were 
carried  to  the  distance  of  300  miles,  and  217  toward  Celebes,  in 
sufficient  quantity  to  darken  the  air. 

The  floating  cinders  to  the  windward  of  Sumatra,  formed,  on 
the  12th  of  April,  a  mass  two  feet  thick  and  several  mile  in  ex- 
tent, through  which  ships  with  difficulty  forced  their  way. 

The  darkness  occasioned  in  the  daytime  by  the  ashes  in  Java 
was  so  profound,  that  nothing  equal  to  it  was  ever  witnessed  in 
the  darkest  night. 

The  area  over  which  the  tremulous  noises  and  other  volcanic 
effects  extended  was  one  thousand  English  miles  in  circumfer- 
ence, including  the  whole  of  the  Molucca  Islands,  Java,  and  a 
considerable  portion  of  Celebes." — Lyell. 

7.  Static  Pressure  in  Volcanoes. — The  enormous  pressure  of  the 
liquid  lava  against  the  inteiior  of  volcanoes,  when  it  is  raised  to 
a  great  height,  is  the  cause  of  the  frequent  eruptions  through  their 
sides.     The  force  requisite  to  raise  lava  to  the  edge  of  the  crater 
of  JEtna,  from  the  level  of  the  base  of  the  mountain,  exceeds  five 
tons  per  square  inch.     In  Cotopaxi,  which  is  19,000  feet  in  height, 
the  force  required  is  ten  tons  per  square  inch :  yet  this  volcano 
has  projected  matter  6000  feet  above  its  summit,  and  once  threw 
a  stone  weighing  200  tons  to  the  distance  of  nine  miles.     Acon- 
cagua, in  Chili,  the  highest  of  all  volcanoes  (23,000  feet),  would 
require  at  its  base,  for  an  eruption  from  the  summit,  a  force  of 
twelve  tons  per  square  inch. 

8.  Characters  of  Lava. — The  melted  matter  ejected  from  vol- 
canoes is  composed  chiefly  of  feldspar  and  augite.     When  the 
former  prevails,  the  lava  is  said  to  be  feldspathic  or  trachyticv 
and  when  the  latter  predominates,  the  lava  is  said  to  be  augitic. 

What  is  said  of  the  static  pressure  in  volcanoes  ?  Of  what  minerals  is  lava 
composed  ? 


60  IGNEOUS    AfcrUNCIES. 

When  lava  is  cooled  near  the  surface  of  the  mass,  it  is  usually 
light  and  porous,  having  been  inflated  with  bubbles  of  gas.  In 
some  cases  these  bubbles  of  gas  are  of  great  size,  and  the  cavities 
constitute  large  caverns.  Sometimes  the  elasticity  of  the  gas  ex- 
plodes the  bubbles,  and  throws  fragments  of  lava  into  the  air. 
When  melted  feldspathic  lava  comes  into  contact  with  water,  the 
water  is  converted  into  steam,  which  causes  the  lava  to  froth  up, 
and  converts  it  into  pumice.  At  the  time  of  the  eruption  of  Skap- 
.tar  Jokul,  in  1783,  there  was  an  island  thrown  up  seventy  miles 
from  land,  and  the  ocean  was  covered  with  vast  quantities  of 
floating  pumice  for  a  distance  of  150  miles.  Dr.  C.  T.  Jackson 
has  made  pumice  from  the  slags  of  furnaces  by  throwing  water 
in  the  path  of  the  running  slag.  It  is,  indeed,  a  common  form  of 
the  slag  of  furnaces. 

When  lava  cools  under  the  pressure  of  a  superincumbent  mass, 
it  is  generally  99  compact  and  solid  as  the  older  rocks.  Some  of 
the  products  of  volcanoes  consist  mostly  of  silex,  and  resemble 
impure  glass  or  the  slag  of  furnaces,  and  frequently  the  artificial 
can  not  be  distinguished  from  the  natural  product. 

II.  Earthquakes. — 1.  One  of  the  most  remarkable  earthquakes 
was  that  which  began  at  Lisbon,  on  the  1st  of  November,  1755. 
A  sound  like  thunder  under  ground  was  heard,  and  in  six  min- 
utes the  greater  part  of  the  city  was  thrown  down,  and  60,000 
persons  had  perished.  The  sea  retired,  and  then  rolled  back  50 
feet  higher  than  its  ordinary  level.  A  new  marble  quay  was  sud- 
denly swallowed  up  with  a  great  concourse  of  people,  and  the 
vortex  drew  down  many  boats  and  small  vessels.  The  highest 
mountains  in  Portugal  were  shaken  from  their  foundations ;  theii 
summits  were  split  and  rent,  and  portions  of  them  were  thrown 
down  into  the  valleys.  The  shock  was  felt  at  sea,  and  a  ship  120 
miles  west  of  St.  Vincent  experienced  a  violent  concussion,  which 
was  probably  occasioned  by  a  wave  of  translation,  that  is,  a  mo- 
tion of  the  water  itself. 

This  earthquake  was  felt  over  a  large  part  of  the  earth.     All 

When  is  lava  porous  ?     What  is  pumice  ?     When  is  lava  compact  ?     Do 
scribe  the  Lisbon  earthquake 


MOTION    OP    EARTflaUAKE».  61 

Europe,  even  to  Norway,  felt  the  shock.  The  waters  of  Loch 
Lomond  (in  Scotland)  rose  two  feet  and  four  inches.  Terrible 
eruptions  and  earthquakes  occurred  in  Iceland.  Springs  through- 
out Europe  and  Great  Britain  became  hot,  and  some  of  them  tur- 
bid. The  north  of  Africa  was  violently  shaken,  and  a  village 
near  Morocco  was  ingulfed  with  8000  or  10,000  persons  in  a  fis- 
sure, which  opened  and  closed  over  them.  The  shock  was  felt 
in  the  West  Indies ;  and  the  waters  of  Lake  Ontario  were  vio- 
lently agitated. 

2.  The  West  Indies  have  been  more  or  less  subject  to  earth- 
quakes since  their  discovery.     In  1692  a  great  earthquake  in- 
gulfed three  quarters  of  the  then  large  ana  opulent  city  of  Port 
Hoyal,  in  Jamaica ;  the  Blue  Mountains,  8000  feet  high,  were 
rent  and  shattered,  and  the  surface  of  the  island  swelled  and 
heaved  like  a  rolling  sea.     In  1843,  Guadaloupe  and  several 
towns  were  suddenly  destroyed. 

3.  The  motion  of  the  ground  in  earthquakes  is  said  to  be  lik« 
that  of  waves  pursuing  each  other  with  great  velocity,  in  many 
cases  of  20  miles  per  minute.     Sometimes  the  force  acts  in  an 
upward  direction,  as  in  the  earthquake  of  Calabria  in  1783,  when 
loose  masses  bounded  into  the  air  to  the  height  of  several  yards, 
and  in  some  of  the  towns  the  pavements  were  thrown  up.     Dur- 
ing the  same  earthquake,  however,  other  places  were  affected 
with  a  force  acting  horizontally.    This  year  there  were  349  shocks 
in  Italy,  the  first  of  which,  February  5th,  t!  threw  down,  in  the 
space  of  two  minutes,  the  greater  part  of  the  houses  in  all  the 
cities,  towns,  and  villages,  from  the  western  flanks  of  the  Apen- 
nines ki  Calabria  Ultra,  to  Messina  in  Sicily,  and  convulsed  the 
whole  country." — Lyell.      On  March  28th,  another  shock  occur- 
red.    The  extent  of  country  convulsed  was  very  great.     Around 
the  city  of  Oppido  as  a  center,  all  the  towns  and  villages  were, 
destroyed  for  twenty-two  miles  in  every  direction.     The  surface 
of  the  country  heaved  like  the  waves  of  the  sea,  and  the  inhabit- 
ants experienced  the  sensation  of  sea-sickness.     The  earth  open- 

What  is  said  of  the  earthquake  of  1692  ?  of  the  motion  of  the  ground  in  the 
earthquake  of  Calabria  ? 


62  IGNEOUS    AGENCIES. 

ed  in  many  places ;  large  masses  were  shaken  down  from  the 
mountains  and  cliffs  of  the  sea ;  deep  lakes  and  fissures  were 
produced,  valleys  were  excavated,  rocks  and  trees  were  thrown 
into  the  air,  the  courses  of  rivers  were  changed,  sand-hills  and 
ridges  were  thrown  up  in  some  places,  and  depressions  were  pro- 
duced in  others. 

The  billowy  motion  has  been  remarked  by  all  who  have  de- 
scribed the  phenomena  of  earthquakes.  It  is  a  cause  of  ridges, 
arches,  and  faults  in  the  rocky  strata.  In  Darwin's  travels  in 
South  America,  it  is  stated  that  an  engineer  who  was  following 
up  an  ancient  river  bed,  found  himself,  on  one  occasion,  suddenly 
going  down  hill. 

4.  The  effects  of  earthquakes,  most  important  in  a  geological 
point  of  view,  are  the  subsidence  and  the  elevation  of  land.  In 
the  year  1772,  Papandayang,  one  of  the  loftiest  volcanoes  of  Java, 
was  in  eruption,  when  the  greater  part  of  the  mountain,  for  a 
space  15  miles  long  and  6  wide,  fell  in  and  disappeared  with  its 
inhabitants.  On  the  other  hand,  the  bed  of  the  sea,  in  the  harboi 
of  Conception  (Chili),  was  raised,  in  1750,  to  the  amount  of  25 
feet,  and  in  1822  the  coast  of  Chili  was  permanently  elevated 
through  an  area  of  100,000  square  miles.  January  16th,  1819, 
an  earthquake  occurred  at  Cutch,  on  the  delta  of  the  Indus.  The 
fort  and  village  of  Sindree  were  submerged,  the  tops  only  of  the 
houses  appearing  above  the  water.  2000  square  miles  of  land 
were  converted  into  a  lake.  Immediately  after  the  shock,  a 
mound  50  miles  long,  15  miles  wide,  and  10  feet  high,  arose 
within  a  few  miles  of  the  place  of  subsidence. 

III.  Thermal  Springs. — Geysers,  or  springs  of  hot  water,  occui 
in  volcanic  countries.  The  most  celebrated  are  those  of  Iceland, 
in  the  southwest  part  of  which  is  an  assemblage  of  perforations 
in  the  earth,  through  which  are  emitted  jets  of  boiling  water. 

The  Great  Geyser  is  an  opening  from  8  to  10  feet  in  diameter, 
in  a  basin-shaped  mound,  Fig.  23,  through  which  a  column  of 

What  is  said  of  the  billowy  motion  ?  What  are  the  most  important  geolog 
ical  effects  ?  What  is  said  of  Papandayang  ?  of  Chili  ?  of  the  Cutch  ?  Where 
are  the  most  celebrated  geysers  ?  Describe  the  Great  Geyser. 


GEYSERS    OF    ICELAND. 
Fig.tt. 


63 


VIEW   OF    THE    GREAT   GEYSER. 


water  is  forced  up  to  the  height  of  150  or  200  feet.  The  water 
»n  its  ascent  is  divided  into  innumerable  jets,  and  descends  in 
showers  of  spray,  as  represented  in  the  figure.  The  action  of 
the  geyser  is  not  constant,  but  intermittent,  there  being  alternate 
periods  of  activity  and  repose. 

Hot  springs  are  also  common  in  countries  which  are  quite 
remote  from  any  existing  volcanic  agency,  but  which  at  no  very 
remote  geological  period  have  been  the  theater  of  volcanic  action. 
In  Arkansas  and  in  Oregon  are  examples. 

In  some  cases  the  heat  is  that  of  boiling  water,  but  there  are 

What  is  said  of  the  temperature  of  thermal  springs  ? 


64  IGNEOUS    AGENCIES. 

all  degrees  of  temperature,  and  the  thermal  character  of  some 
springs  is  so  slight  as  to  be  detected  only  by  continued  therrno- 
metrical  observations. 

In  most,  if  not  in  all  cases,  thermal  springs,  which  are  distant 
from  active  volcanoes,  are  situated  near  ancient  volcanic  rocks, 
or  near  chains  of  mountains  which  were  broken  up  and  elevated 
by  the  igneous  agency  of  former  epochs.  The  latter  is  the  case 
with  the  hot  springs  of  Virginia  and  many  others  in  the  United 
States. 

SECTION  II— SUBMARINE  IGNEOUS  AGENCIES. 

I.  Volcanic  Islands. — Many  islands  of  considerable  size  have 
been  seen  to  rise  from  the  sea,  and  many  others  composed  of 
lava  are  doubtless  of  volcanic  origin.  Authentic  narratives  of 
such  events  in  remote  ages  are  limited  to  the  Mediterranean  Sea, 
In  the  Grecian  Archipelago  there  is  a  group  of  islands,  of  which 
Santorini  is  the  chief,  several  of  which  have  been  thrown  up  at 
different  times. 

In  July,  1831,  a  volcano  rose  up  through  the  sea  off  the  coast 
of  Sicily,  and  was  called  Graham's  Island.  Fig.  24  represents  its 

Fig.  24. 


GRAHAM'S  ISLAND,  18tH  OF  JULY,  1831. 
appearance  on  the  18tb  of  July,  and  Fig.  25  on  the  4th  of  August, 

What  is  said  of  the  situation  of  thermal  springs  ?     What  is  said  of  volcanic 
islands  ?     Describe  Graham's  Island. 


SUBMARINE    ERUPTIONS.  65 

Fig.  25. 


GRAHAM'S  ISLAND,  4in  OJF  AUGUST,  1831. 

as  seen  by  Corrao.  In  August  it  was  180  feet  high  and  1£  miles 
in  circumference  ;  but  the  part  above  the  water,  being  composed 
of  loose  materials,  disappeared  in  two  or  three  years,  leaving  a 
rocky  shoal.  The  Azores  and  the  Aleutian  Isles  have  been  re- 
peatedly increased  by  new  volcanic  islands.  In  1814,  near  Una- 
laschka,  an  island  was  raised  with  a  peak  3000  feet  high.  Many 
new  islands  have  been  thrown  up  near  the  shores  of  Iceland, 
and  some  of  them  have  since  subsided.- 

II.  Submarine  earthquakes  not  unfrequently  furnish  proofs  of 
their  occurrence  in  sudden  and  extraordinary  waves.  A  few 
years  since,  at  the  Sandwich  Islands,  a  series  of  such  waves  swept 
away  a  village  near  the  shore.  Perhaps  a  sudden  rise  and  fall 
of  one  or  two  feet,  which  was  observed  in  the  harbor  cf  Nan- 
tucket,  in  June,  1836,  may  be  referred  to  such  a  cause. 

Volcanic  forces  may  be  active  in  the  lowest  depths  of  the  ocean. 
At  the  depth  of  five  miles,  the  pressure  of  the  superincumbent 
mass  of  water  is  so  great  that  the  most  powerful  volcanic  agency 
would  act  silently  and  be  unfelt  at  the  surface.  With  that  press- 
ure the  water  would  become  red  hot  without  bursting  into  steam, 
and  currents  of  incandescent  lava  might  flow  quietly  down  the 

What  are  the  effects  of  submarine  earthquakes  ?  What  must  be  the  char- 
acter of  eruptions  at  great  depths  under  the  ocean  1 


66  IGNEOUS    AGENCIES. 

sides  of  submarine  mountains.  But  the  effects  on  the  chemical 
constitution,  and  on  the  crystalline  structure  of  the  melted  and 
cooling  mass,  would  be  great.  Doubtless  many  of  the  older  ig- 
neous rocks  had  such  an  origin. 

SECTION  III.— SUBTERRANEAN  IGNEOUS  AGENCIES. 

The  history  of  igneous  agency  on  the  surface  of  the  earth  nat 
u rally  leads  us  to  look  within  for  its  source.     We  shall  briefly 
proceed  from  the  less  to  the  more  general  conclusions,  until  we 
arrive  at  a  theory  sufficiently  comprehensive  to  embrace  all  the 
phenomena  of  igneous  action. 

I.  Theory  of  Geysers. — The  most  probable  theory  of  geysers 
has  been  well  illustrated  by  the  following  figure.  (Lyell's  Prin- 
ciples, Am.  ed.,  i.,  472.) 

4<  Suppose  water  percolating  from 
the  surface  of  the  earth  to  penetrate 
into  the  subterranean  cavity  A  D  by 
the  fissures  F  F,  while  at  the  same 
time  steam  at  an  extremely  high 
temperature,  such  as  is  commonly 
given  out  from  the  vents  of  lava  cur- 
rents during  congelation,  emanates 
j  from  the  fissures  C. 


~^-'—-—.     n  .  >. 


"A  portion  of  the  steam  is  at 
first  condensed  into  water,  while  the 
temperature  of  the  water  is  ele- 
vated by  the  latent  heat  thus  evolv- 
ed, till  at  last  the  lower  part  of  the 
cavity  is  filled  with  boiling  water,  and  the  upper  part  with  steam 
under  high  pressure.  The  expansive  force  of  the  steam  becomes 
at  length  so  great  that  the  water  is  forced  up  the  fissure  E  B,  and 
runs  over  the  rim  of  the  basin.  When  the  pressure  is  thus  di- 
minished, the  steam  in  the  upper  part  of  the  cavity  A  expands, 
until  all  the  water  [in  the  upper  part  of  A  D]  is  driven  into  the 
pipe  ;  and  when  this  happens  the  steam  also  rushes  up  with  great 
velocity." 

II.  Theory  of  Volcanoes. — 1.  The  same  theory  may  be  applied 
to  volcanoes,  if  we  suppose  that  the  seat  of  operations  is  on  a 

Where  is  the  source  of  igneous  agency  ?     Describe  the  theory  of  geysers. 
How  may  this  theory  be  applied  to  volcanoes  1 


DISTRIBUTION    OP    VOLCANOES.  67 

mass  of  molten  lava  at  the  depth  of  several  miles.  Water  enter- 
ing is  converted  into  steam,  which  forces  up  the  lava  in  the  crater 
of  some  neighboring  volcano  or  through  the  crust  of  the  earth. 
That  water  is  an  important  agent  in  volcanic  eruptions  would 
seem  to  be  proved  by  the  great  quantities  of  steam  which  escape, 
and  by  the  hydrochloric  acid  and  salt  emitted,  which  the  salt 
water  may  have  furnished.  In  South  America,  even  fishes  have 
been  discharged. 

It  may  perhaps  be  objected  to  any  theory  which  shall  make 
the  expansive  force  of  steam  the  sole  agency,  by  which  lava  is 
elevated  many  thousand  feet,  that  the  force  may  not  be  sufficient. 
When  water  is  converted  into  steam  at  a  temperature  of  800°, 
nearly  a  red  heat,  it  merely  doubles  its  volume,  and  has  a  press- 
ure of  only  two  tons  per  square  inch.  But  since  the  pressure 
of  lava  in  most  volcanoes  exceeds  this  amount,  it  would  seem  that 
the  ordinary  source  of  the  great  power  of  steam  by  increase  of 
heat,  viz.,  the  increased  quantity  in  a  given  space,  would  avail 
little.  The  resistance  of  the  superincumbent  matter  would  be 
such  that  the  water  would  not  double  its  bulk.  The  universal 
law  of  expansion  by  increments  of  heat  would  hold  good  ;  but,  al- 
though the  application  of  the  law  under  such  circumstances  may 
not  be  obvious,  yet  it  may  be  conjectured  that  the  water  would 
merely  be  heated  red  hot,  without  a  very  considerable  expansion. 

2.  The  geographical  distribution   of  volcanoes  tends  to  the 
same  conclusion.     On  inspection  of  the  following  map,  Fig.  27, 
on  which  the  volcanic  regions  are  indicated  by  the  shaded  parts, 
it  will  be  seen  that  volcanoes  are,  with  a  few  exceptions,  situ- 
ated near  the  ocean.     About  two  thirds  of  the  number  are  on 
islands,  and  of  the  remaining  third  nearly  all  are  within  a  short 
distance  of  the  coast.     In  Mexico  and  in  Central  Asia  there  are 
a  few  exceptions  to  this  general  statement.     It  will  be  seen,  also, 
that  most  volcanoes  are  arranged  in  lines  or  zones  of  great  ex- 
tent. 

3.  The  history  of  volcanoes  and  earthquakes  has  shown  us  that 

What  objection  to  this  theory  of  volcanoes  ?     What  is  said  of  their  geograph- 
ical distribution  ? 


68 


IGNEOUS    AGENCIES. 
Fig.  27. 


the  source  of  their  action  is  very  deeply  seated  in  the  earth.  This 
is  especially  manifest  from  the  quantity  of  matter  erupted. 

The  single  eruption  of  Skaptar  Jokul,  in  1783,  protruded  a 
mass  of  lava  exceeding  the  bulk  of  the  entire  mountain.  In  1660, 
it  was  computed  that  the  ejections  of  Mount  ./Etna,  if  collected, 
would  form  a  mass  twenty  times  the  size  of  the  original  mount- 
ain ;  yet  the  subsequent  eruptions  do  not  indicate  any  exhaustion 
of  the  source.  It  was,  therefore,  a  correct  idea  of  Seneca,  who 
says  that  the  volcanic  mountain  does  not  supply  the  fire,  but 
merely  affords  it  a  passage.  Volcanoes  are  only  chimneys  over 
the  subterranean  fires. 

4.  But  we  may  go  further,  and  affirm  that  these  fires  are  suffi- 
ciently extensive  to  furnish  a  communication  between  distant  vol- 
canoes. This  conclusion  unavoidably  follows  from  their  alternate 
action,  from  their  relations  to  earthquakes,  and  from  the  geograph- 
ical extent  of  the  latter.  From  the  numerous  facts  which  sustain 
this  conclusion,  we  can  present  only  a  few  illustrations. 

In  1797,  the  volcano  of  Pasto,  in  the  western  part  of  Columbia, 
emitted  a  volume  of  smoke  for  three  months,  which  ceased  at 
the  moment  when  a  violent  earthquake,  with  an  eruption  of  mud 
and  water,  of  vapors  and  flames,  occurred  at  the  distance  of  180 
miles.  Vesuvius  and  Ischia  have  alternated  with  each  other. 
Eruptions  of  the  latter  were  frequent  and  violent  in  the  earlier 

What  is  proved  by  the  quantity  of  matter  erupted  ?  Give  examples.  What 
ia  said  of  the  alternate  action  of  volcanoes  ? 


THEORY  OF  INTERNAL  HEAT  69 

ages,  while  Vesuvius  was  quiet  until  A.D.  79,  when  it  over- 
whelmed Herculaneum  and  Pompeii.  Ischia  has  since  had  its 
period  of  repose,  and  Vesuvius  of  activity. 

It  has  been  observed  that,  from  the  commencement  of  the  thir- 
teenth to  the  latter  half  of  the  seventeenth  century,  earthquakes 
in  Syria  and  Judea  almost  entirely  ceased,  while  Southern  Italy 
suffered  extraordinary  convulsions.  A  comparison  of  their  his- 
tory leads  to  the  conclusion  that  both  are  not  violently  affected 
at  the  same  time,  whence  it  has  been  inferred  that  a  subterranean 
connection  exists  between  regions  nearly  fifteen  hundred  miles 
distant. 

In  1811,  South  Carolina  was  convulsed  with  earthquakes, 
which  continued  until  Laguira  and  Caraccas  (South  America) 
were  destroyed.  At  the  same  time  the  valley  of  the  Mississippi 
was  convulsed,  especially  under  New  Madrid.  New  lakes,  20 
miles  in  extent,  were  formed,  and  others  were  drained  ;  the  earth 
undulated  like  the  ocean,  and  split  into  frightful  chasms.  These 
chasms  were  in  a  direction  from  southwest  to  northeast,  and  the 
people,  soon  observing  it,  felled  trees  at  right  angles  to  this  di- 
rection, and  placed  themselves  upon  them.  Many  were  thus 
saved  from  being  swallowed  up. 

The  directions  of  these  chasms  were  that  which  would  have 
been  produced  by  an  undulating  force,  propagated  in  a  northwest 
and  southeast  line ;  and  it  is  worthy  of  notice  that  New  Madrid, 
in  the  valley  of  the  Mississippi,  South  Carolina,  and  Caraccas, 
are  nearly  in  this  direction.  This  circumstance,  and  especially 
the  coincidence  in  time,  indicate  a  subterranean  communication 
between  these  places,  whose  extremes  are  distant  2500  miles. 

The  extent  to  which  the  earthquake  in  1755  was  felt  has  been 
mentioned  (p.  61),  and  indicates  a  seat  of  subterranean  action 
under  a  very  considerable  portion  of  the  crust  of  the  earth. 

The  influence  of  earthquakes  may  be  considerably  extended 
by  the  transmission  of  vibrations  through  the  solid  rocks.  But 
the  extent  of  country  affected  in  this  manner  can  not  be  much 
larger  than  that  which  is  directly  acted  upon.  A  mere  transmit- 
ted vibration  could  not  affect  the  quantity  and  temperature  of  the 
waters  in  thermal  springs  and  render  them  turbid,  which  was  re- 
markably the  case  throughout  Europe  in  the  Lisbon  earthquake. 
Says  Baron  Humboldt,  in  the  view  of  such  facts  :  "  They  demon- 

Describe  the  earthquakes  of  1811.  What  is  said  of  the  vibratory  influence 
of  earthquakes  ?  What  is  Humboldt's  opinion  ? 


70  IGNEOUS    AGENCIES. 

strate  that  these  forces  act,  not  superficially  in  the  outward  crust 
of  the  earth,  but  at  immense  depths  in  the  i  iterior  of  our  planet/'' 

III.  Theory  of  Internal  Heat. — Thus  far,  most  geologists  are 
agreed ;  but  if  we  extend  our  inquiries  further,  and  require  a 
more  definite  theory  of  the  source  of  volcanic  fires,  we  then  find 
some  difference  of  opinion. 

Let  us  consider  the  theory  which  is  most  in  favor,  and  which 
supposes  that  the  whole  interior  of  the  earth  is  in  a  state  of  fusion, 
within  a  crust  of  50  to  100  miles  in  thickness.  According  to  this 
theory,  earthquakes  are  the  effects  of  the  heaving  of  this  melted 
interior,  occasioned,  perhaps,  by  steam  or  chemical  action,  and 
volcanoes  are  the  safety-valves  through  which  earthquakes  are 
relieved. 

In  support  of  this  theory,  it  is  urged  that  it  affords  a  satisfactory 
explanation  of  the  great  extent  of  earthquakes  and  of  the  altern- 
ation between  distant  volcanoes,  of  the  great  quantity  of  matter 
ejected  through  the  latter,  and  of  their  being  associated  together 
along  lines,  or  in  groups  where  the  crust  of  the  earth  may  be  sup- 
posed to  be  of  less  thickness.  The  undulatory  motion  of  earth- 
quakes would  be  merely  the  waving  of  the  crust. 

The  theory  of  internal  heat,  however,  reposes  chiefly  on  experi 
ments  made  upon  the  temperature  of  mines  and  Artesian  wells, 
which  concur  in  the  interesting  result  that  in  all  places  the  tem- 
perature of  the  earth  increases  after  passing  below  the  stratum 
of  surface  temperature,  in  a  ratio,  which  varies  in  different  places 
from  1°  Fahr.  for  25  feet  of  descent,  to  1°  for  70  feet,  but  which 
is  quite  constant  in  the  same  place.  From  the  very  numerous 
observations  which  have  been  made,  we  select  a  few  examples  : 

"At  the  Dolcoath  mine  of  Cornwall  (England),  the  mean  an- 
nual temperature  at  the  surface  of  the  ground  is  50°  ;  of  a  spring 
1440  feet  below,  82°  ;  and  of  the  rock  three  feet  three  inches 
within  its  surface,  and  1381  feet  deep,  76'6°.  At  the  silver  mine 
of  Gruanaxuato  the  mean  annual  temperature  -afc  the  surface  is 
68-8°,  and  the  temperature  of  a  spring  1713  feet  below  is  98'3°. 
A  single  experiment  in  the  deepest  coal  mine  in  Greac  Britain, 

What  is  the  theory  of  internal  heat  ?  How  does  it  ejr^lain  tne  igneous 
agencies  ?  What  is  the  direct  argument  for  this  theory  \ 


THEORY  OF  INTERNAL  HEAT.  71 

near  Sunderland,  gave  the  following  results  :  depth  of  the  place 
of  observation,  1584  feet;  below  the  level  of  the  sea,  1500  feet 
Mean  annual  temperature  at  the  surface,  47'6° ;  temperature  on 
the  day  of  observation  (Nov.  15,  1834),  49°  ;  do.  of  the  air  at  the 
bottom  of  the  pit,  64°  ;  close  to  the  coal,  68°  ;  do.  of  water  col- 
lected at  bottom,  67°  ;  do.  of  salt  water  issuing  from  a  hole  made 
the  same  day,  70' 1° ;  do.  also  of  gas  rising  through  the  water, 
72'7° ;  do.  of  the  front  of  the  coal,  68°.  Hence  the  heat  increases 
at  the  rate  of  about  a  degree  for  every  60  feet." — Hk. 

At  Berlin  (Prussia),  the  mean  temperature  is  47*1°  ;  the  tem- 
perature of  the  water  of  an  Artesian  well  at  the  depth  of  675  feet 
is  67*6°.  At  Paris,  the  mean  temperature  is  51'1°  ;  the  temper- 
ature of  an  Artesian  well  1800  feet  deep  (the  deepest  in  the 
world),  is  83°.  In  Wurtemburg,  the  water  obtained  in  Artesian 
wells  is  used  with  success  to  prevent  the  stopping  of  machinery 
by  the  freezing  of  the  water  which  carries  it,  and  also  for  warm- 
ing a  paper  manufactory.* 

As  similar  results  have  been  obtained  in  all  cases,  it  is  inferred 
that  the  heat  would  be  found  to  continue  to  increase,  if  we  were 
able  to  penetrate  much  deeper,  until,  at  the  depth  of  one  or  two 
miles,  we  should  reach  the  temperature  of  boiling  water.t  At 
the  same  ratio  of  increase,  the  heat  at  a  depth  of  forty  miles 
would  be  sufficient  for  the  fusion  of  all  known  rocks. 

It  has  been  objected  to  this  theory,  that  the  diffusion  of  heat 
through  the  liquid  interior  should  melt  also  the  crust  of  the  earth. 
If  it  were  supposed  that  the  heat  continued  to  increase  through 
all  the  melted  nucleus  to  the  center,  in  the  same  ratio  in  which 
it  increases  through  the  solid  crust,  the  objection  would  be  fatal 
to  any  such  theory.  But  we  can  not  see  any  more  difficulty  in 
conceiving  that  the  earth  has  had  a  crust  50  miles  in  thickness 
congealed  in  the  lapse  of  ages,  than  that  a  body  of  water  should 

*  Warm  springs  which  rise  from  deep  sources,  have  teen  used  for  warming 
conservatories  and  irrigating  gardens.  It  is  said  that  a  piece  of  ground  at  Er- 
furt (Germany),  which  is  thus  kept  at  an  equable  and  high  temperature,  yields 
to  its  proprietor  an  annual  profit  of  $60,000,  derived  from  raising  salad. 

t  On  account  of  the  great  pressure,  it  is  not  to  be  inferred  that  water  would 
boil  at  this  or  at  any  other  depth.  See  p.  67. 

What  is  said  of  Artesian  wells  ?  of  the  heat  at  the  depth  of  one  or  two  miles  ? 
at  the  depth  of  forty  miles  ?  What  objection  to  the  theory  ?  What  reply  ia 
made? 


72  CGNEOUS    AGENCIES. 

be  incrusted  with  ice  by  a  similar  process.  It  might  as  well  be 
urged  that  it  is  impossible  for  a  pond  of  water  to  be  frozen  over, 
because  the  diffusion  of  heat  through  the  water  would  melt  the 
ice. 

Another  theory  (of  Sir  Charles  Lyell)  supposes  that  there  are, 
beneath  the  crust  of  the  earth,  immense  reservoirs  and  subterra- 
nean channels  of  lava,  whose  action  is  the  source  of  eruptions 
and  of  earthquakes.  The  ground  of  preference  for  this  theory 
on  the  part  of  its  advocates  is,  that  it  is  sufficient  to  account  for 
all  the  phenomena  of  earthquakes  and  volcanoes,  and  for  the  tem- 
perature of  mines  and  of  Artesian  wells.  If,  however,  these  res- 
ervoirs and  channels  are  thus  numerous,  this  theory  is  obviously 
exposed  to  the  objection  which  has  been  urged  against  the  former ; 
and  the  existence  of  partitions  protected  from  the  colder  temper- 
ature of  the  surface  by  miles  of  non-conducting  materials,  but  ex- 
posed to  the  action  of  these  adjacent  lakes  of  fire,  is  inconsistent 
with  the  laws  of  the  equilibrium  of  heat  in  liquids. 

SECTION  IV.— GENERAL  RESULTS  OF  IGNEOUS  AGENCY. 

The  general  effects  of  igneous  agency  may  be  thus  summed 
up: 

1.  The  transfer  of  matter  from  the  interior  to  the  surface  of  the 
earth. 

2.  The  discharge  of  gases  and  of  pent-up  vapors,  which  gives 
relief  to  earthquakes. 

3.  The  production  of  fissures,  which,  being  filled  with  lava,  form 
dikes. 

4.  The  formation  of  peculiar  kinds  of  stratified  rocks  by  dis 
charges  into  the  sea. 

5.  The  elevation  of  parts  of  the  earth's  crust. 

6.  The  depression  of  parts  of  the  earth's  crust. 

7.  The  lifting  up  of  strata  out  of  a  horizontal  position. 

8.  The  burial  of  animals,  of  plants,  and  of  works  of  art,  some- 
times without  entirely  destroying  them. 

State  Sir  C.  Lyell's  theory;  the  argument  for  it  and  against  it.  What  is 
the  first-mentioned  effect  of  igneous  agency  ?  the  second  ?  the  third  ?  &c 


RESULTS    OF    AQUEOUS    AND    IGNEOUS    AGENCIES.  73 

9.  The  heating  of  thermal  springs. 

10.  An  increase  of  the  erosive  action  of  water.     This  effect 
appears  in  the  floods  produced  by  the  sudden  melting  of  snow 
and  ice  in  volcanoes ;  but  especially  in  the  waves  of  translation, 
which  are  produced  by  earthquakes.     It  is  well  known  that  or- 
dinary waves  have  but  little  onward  motion,  except  when  meet- 
ing a  shore.     On  the  contrary,  in  waves  of  translation,  there  is  a 
horizontal  motion  of  the  water,  which  greatly  increases  its  ero- 
sive power. 


CHAPTER  III. 

JOINT  EFFECTS  OF  AQUEOUS  AND  IGNEOUS-  AGENCIES. 

THE  two  great  powers  which  we  have  thus  considered,  fire  and 
water,  are  to  some  extent  in  their  geological  effects,  as  they  are 
in  their  nature,  antagonist  forces.  Running  water  is  constantly 
removing  the  land  by  slow  degrees  from  higher  to  lower  levels, 
and  into  the  sea,  while  volcanoes  are  raising,  from  within  the 
•crust  of  the  earth,  to  a  greater  or  less  height, 'their  floods  of 
melted  rocks.  Earthquakes  are  also  engaged  in  lifting  whole 
countries  by  violent  shocks,  while  some  unknown  power,  per- 
haps the  plication  of  the  crust  of  the  earth^  is  more  gradually  ef- 
fecting the  same  result.  As,  however,  water  in  some  cases  re- 
verses its  usual  mode  of  operation,  and  in  springs  raises  its  sol- 
uble contents  from  deep  places  and  deposits  them  on  the  surface 
of  the  ground,  so,  on  the  other  hand,  the  igneous  agencies  not 
unfrequently  reverse  the  more  common  process  of  elevation,  and 
we  see  earthquakes  swallowing  down  large  portions  of  land.  It 
is  obvious  that  rivers  carry  into  the  sea  an  amount  of  sediment 
generally  exceeding  the  eruptions  of  volcanoes,  and  if  the  ele- 
vatory  effects  of  earthquakes  did  not  exceed  those  of  depression, 

In  what  way  are  heat  and  water  antagonist  forces  ?  What  is  the  effect  of 
•prings  ?  What  is  the  average  result  of  these  agencies  ? 

D 


/4  INORGANIC   AGENCIES. 

the  general  tendency  would  be  to  reduce  the  earth  to  a  uniform 
level.  But  if,  as  is  stated,  the  great  earthquake  of  Chile  raised 
an  extent  of  100,000  square  miles  three  feet  in  height,  here  was 
the  amount  of  two  and  three  fourths  millions  of  millions  of  cubic 
feet  raised  at  once  above  the  sea  level.  Similar  elevations  may 
occur  in  places  which  are  at  a  distance  from  the  sea,  and  there- 
fore show  no  obvious  proof  of  elevation. 

Elevation  of  land  in  some  cases  is  going  on  gradually,  without 
any  apparent  earthquake  shocks.  This  is  remarkably  the  case 
with  the  country  around  the  Baltic  Sea,  which  is  rising  at  the  rate 
of  two  or  three  feet  per  century.  This  is  shown  by  the  marks 
made  at  various  periods  to  designate  the  high-water  level,  and  is 
confirmed  by  the  marine  shells  of  species  now  living  on  the  shore, 
which  are  found  from  10  to  200  feet  above  the  present  level  of 
the  water,  and  50  miles  inland. 

The  coast  of  Greenland  appears  to  be  undergoing  a  gradual  de- 
pression. In  this  country  the  Northern  States  appear  to  have  been 
rising  during  a  geological  period  not  very  remote,  and  perhaps  the 
process  is  yet  slowly  going  on. 

The  great  problem,  therefore,  of  the  general  tendency  of  ex- 
isting forces  is  as  complicated  as  it  is  grand  in  its  numerous  and 
conflicting  elements. 


CHAPTER  IV. 

INORGANIC  AGENCIES  NEITHER  AQUEOUS  NOR  IGNEOUS. 

THERE  are  some  other  physical  agencies,  of  more  or  less  im- 
portance, which  we  have  not  introduced  in  our  classification,  be- 
cause  they  are  of  limited  extent.  Rocks  are  sometimes  split  by 
lightning,  and  terrestrial  magnetism  or  rather  galvanism  has  been 
supposed  to  exert  an  important  influence,  especially  in  producing 

Give  an  example  of  a  great  amount  of  elevation ;  of  gradual  elevation ;  of 
gradual  depression.  What  effects  are  produced  by  lightning  and  by  terrestrial 
magnetism  ? 


CORALS.  75 

metallic  veins.  In  districts  of  fine  sand,  winds  exert  an  import- 
ant agency  in  their  distribution.  It  is  well  known  that  many  of 
the  remains  of  the  ancient  Egyptian  architecture  are  more  or  less 
buried  in  impalpable  dust.  "We  are  familiar  with  the  accounts  of 
caravans  on  the  great  deserts  of  Northern  Africa,  which  have 
been  overtaken  and  buried  by  moving  sand.  In  Europe  some 
villages  have  been  destroyed  by  the  same  cause.  A  few  exam- 
ples of  such  sands  in  this  country  are  known,  but  have  not  at- 
tracted much  attention. 


CHAPTER  V. 
ORGANIC   AGENCIES. 

Tne  operation  of  organic  agencies  is  of  great  interest  to  the 
geologist,  because  it  shows  how  extensive  rock  formations  are  and 
have  been  formed.  It  is  a  circumstance  truly  remarkable,  that 
animals  the  most  minute,  nearly  or  quite  invisible  to  the  naked 
eye,  and  among  the  lowest  in  the  scale  of  beings,  are  those  only 
which  are  forming  solid  rocks  or  deposits  of  sufficient  magnitude 
to  engage  the  attention  of  the  geologist. 

SECTION  L— CORALS. 

The  most  important  organic  agency  undoubtedly  is  to  be  found 
in  these  well-known  structures. 

I.  The  Animals. — The  animals  which  construct  corals  belong 
to  the  class  polypi,  or  polypes,  and  consist  of  a  homogeneous  fleshy 
bag,  open  at  one  extremity,  which  is  fringed  with  tubercles. 
The  polypi  are,  however,  very  minute,  seldom  exceeding  the  size 
of  a  pea,  more  frequently  less  than  a  pin's  head,  or  are  even  invisi- 
ble. They  have  the  remarkable  property  of  living  united  in  one 
common  mass,  so  that  whatever  is  swallowed  and  digested  by 

What  is  the  agency  of  winds  ?     What  is  the  rank  of  those  animals  which 
produce  important  geological  effects  ?     What  is  said  of  the  animals  that  con- 
tract corals  ? 


?6  ORGANIC    AGENCIES. 

each,  contributes  to  the  nourishment  of  the  community  by  a  com- 
mon circulation.  The  solid  coral  is  not  a  structure  voluntarily 
made  by  them,  but  a  secretion  in  which  they  have  as  little  design 
as  the  oyster  in  secreting  his  shell,  or  a  quadruped  in  the  growth 
of  its  bones. 

II.  Temperature  in  whicJi  Corals  grow. — One  interesting  result 
of  the  recent  Exploring  Expedition  has  been  the  knowledge  of 
the  temperature  requisite  for  the  existence  of  these  rock-building 
animals.     In  seas  whose  temperature  is  below  66°  they  do  not 
flourish,  and  hence  along  the  western  coast  of  South  America, 
where  the  water  is  cooled  by  an  Antarctic  current,  coral  reefs  do 
not  exist,  while  in  the  same  latitude  on  the  eastern  coast  they  are 
very  extensive.     Nor  do  they  build  at  great  depths,  as  was  once 
supposed,  but  only  in  water  not  exceeding  a  few  fathoms.     Most 
of  the  deep  soundings  in  tropical  seas  indicate  a  temperature  far 
too  low  for  their  existence.     In  colder  waters,  many  species  of 
polypes  occur,  but  they  do  not  construct  extensive  reefs. 

III.  Varieties  of  Coral  Reefs. — Coral  reefs  are,  for  the  most 
part,   either  fringing  or  barrier  reefs,  or  they  inclose  only  a 
smooth  body  of  water  called  a  lagoon. 

1.  Fringing  reefs  are  those  which  occur  along  the  shore.     In 
their  origin  coral  reefs  may  all  have  been  fringing. 

2.  Barrier  reefs  are  more  or  less  parallel  with  the  shore,  but 
are  separated  from  it  by  a  broad  and  deep  channel.     When  an 
island,  which  is  fringed  with  living  corals,  subsides  beneath  the 
waters  very  slowly,  the  reef  is  built  up  to  the  surface  of  the  wa- 
ter as  fast  as  the  land  sinks.     After  a  certain  period,  the  island  ia 
contracted  by  its  submergence,  and  the  reef  becomes  a  barrier 
reef,     a  a,  Fig.  28,  are  barrier  reefs,  and  b  b,  the  water  between 
the  island  and  the  reef. 


What  is  the  origin  of  coral?     At  what  temperature  do  coral  reefs  growt 
fct  what  depths?     What  are  fringing  reefs ?     What  barrier  reefs? 


CORAL    REEFS. 


77 


Fig.  29. 


3.  Lagoon  reefs  are  formed  in  the  last  stage  of  this  process. 
When  the  island  has  disappeared,  we  have  a  circular  reef  inclos- 
ing a  lagoon.  Fig.  29  rep- 
resents a  section  across  an 
island  inclosing  a  lagoon, 
b  b.  Such  circular  reefs 
with  a  diameter  from  one  to  thirty  miles,  are  common  in  the  Pa- 
cific, and  were  formerly  supposed  to  be  on  the  summits  of  volca- 
noes. The  following  is  a  view  of  Whitsunday  Island,  Fig.  30, 
in  which  the  circular  reef  has  become  habitable. 

Fig.  30. 


VIEW    OF   WHITSUNDAY   ISLE. 

It  is  thus  easy  to  determine  whether  the  movement  of  islands 
is  that  of  emergence  or  subsidence.  Since  it  is  not  probable  that 
many  islands  are  stationary  through  periods  which  are  geologic- 
ally long,  it  may  be  correctly  inferred,  from  the  existence  of  fring- 
ing reefs  on  islands,  that  the  process  is  that  of  emergence ;  a  con- 
clusion which  is  sustained  by  the  independent  evidence  of  ancient 
sea-lines  and  corals  within  the  island.  If,  however,  the  reefs  are 
separated  from  the  land  by  broad  and  deep  channels,  the  island 
is  in  the  process  of  subsidence.  Near  such  reefs  dead  corals  are 
found  several  hundred  feet  below  the  depth  at  which  they  could 
have  been  formed. 

IV.  Extent  of  Coral  Reefs. — Coral  reefs  are  very  numerous  in 
many  parts  of  the  Indian  and  Pacific  Oceans,  and  constitute  one 


What  are  lagoon  reefs  ?     What  may  be  inferred  from  fringing  reefs  ? 
from  barrier  reefs  ?     What  is  said  of  the  extent  of  coral  reefs  ? 


What 


78  ORGANIC    AGENCIES. 

of  the  greatest  dangers  of  navigation.  Notwithstanding  the  mi- 
nuteness of  the  animals,  reefs  of  vast  extent  are  described. 

"  On  the  eastern  coast  of  New  Holland  is  a  reef  350  miles 
long.  Disappointment  Islands  and  Duff's  Group  are  connected 
by  500  miles  of  coral  reefs,  over  which  the  natives  can  travel 
from  one  island  to  another.  Between  New  Holland  and  New 
Guinea  is  a  line  of  reefs  700  miles  long,  interrupted  in  no  place 
by  channels  more  than  thirty  miles  wide.  A  chain  of  islets,  480 
geographical  miles  long,  has  long  been  known  by  the  name  of  the 
Maldivas.  Some  groups  in  the  Pacific,  known  as  the  Danger- 
ous Archipelago,  are  from  1100  to  1200  miles  long,  and  from 
300  to  400  miles  broad." — Hk. 

V.  Rate  of  Increase. — It  has  been  supposed,  on  account  of  the 
existence  of  shells  nearly  buried  in  the  substance  of  corals,  while 
the  mollusca  were  yet  living,  that  the  growth  of  corals  was  rapid. 
But  Mr.  Couthuoy  (zoologist  of  the  Exploring  Expedition)  finds 
that  in  such  cases  the  animals  in  the  shells  have  excavated  the 
cavity  in  the  reef.  On  the  other  hand,  the  growth  is  so  slow  as 
not  to  present  any  very  satisfactory  data  for  determining  its  rate. 
Thus  the  most  stupendous  effects  are  produced  not  only  by  the 
feeblest  agents,  but  by  an  imperceptible  progress.* 

"  I  saw  the  living  pile  ascend, 
The  mausoleum  of  its  architects, 
Still  dying  upward  as  their  labors  closed ; 
Slime  the  materials,  but  the  slime  was  turned 
To  adamant  by  their  petrific  touch. 

"  Frail  were  their  frames,  ephemeral  their  lives, 
Their  masonry  imperishable.     All 
Life's  needful  functions,  food,  exertion,  rest, 
By  nice  economy  of  Providence, 
Were  overruled,  to  carry  on  the  process 
Which  out  of  water  brought  forth  solid  rock. 
Atom  by  atom,  thus  the  mountain  grew 
A  coral  island,  stretching  east  and  west ; 
Steep  were  the  flanks,  with  precipices  sharp, 

Descending  to  their  base  in  ocean  gloom. 
******** 

"  Compared  with  this  amazing  edifice, 
Raised  by  the  weakest  creatures  in  existence, 
What  are  the  works  of  intellectual  man 
His  temples,  palaces,  and  sepulchers  ? 
Dust  in  the  balance,  atoms  in  the  gale. 
Compared  with  these  achievements  in  the  deep, 

What  is  said  of  the  growth  of  coral  reefs  ? 


ANIMALCULES.  79 

SECTION  II.-ANIMALCULES. 

The  least  of  all  the  animal  kingdom  rank  next  to  polypes  in 
importance  as  geological  agents.  Some  animalcules  are  visible 
to  the  naked  eye,  but  others  are  only  one  twenty-four  thousandth 
of  an  inch  in  diameter,  and  a  number  equal  to  the  entire  popula- 
'tion  of  the  globe  might  sport  freely  in  a  single  drop  of  water; 
yet  their  remains  constitute  strata  which  are  many  feet  in  thick- 
ness. The  part  most  important  in  this  connection  is  the  shelly 
with  which  a  majority  of  the  species  are  furnished.  Fragile  as 
such  shells  might  be  supposed  to  be,  yet,  as  they  consist  of  silex, 
they  retain  their  original  form  and  structure  for  indefinite  periods 
of  time.  Silicious  marl,  an  impalpable  pulverulent  deposit,  which 
is  found  usually  beneath  the  beds  of  peat  in  Massachusetts  and 
other  places,  chiefly  consists  of  these  shells  to  the  depth  of  sev- 
eral feet. 

The  vast  quantity  of  these  deposits  is  less  astonishing  when 
we  consider  the  fecundity  of  animalcules,  some  of  which  will  have 
millions  of  descendants  in  a  few  days.  Thus  one  individual  of  the 
species  Hydatina  senta  in  twelve  days  may  produce  16,000,000, 
and  one  of  another  species  in  four  days  170,000,000,000 ;  and 
Ehrenberg,  to  whom  science  is  indebted  more  than  to  all  others 
on  this  subject,  affirms,  that  if  the  price  of  tripoli  (rotten  stone  or 
polishing  powder,  which  is  composed  of  their  shells)  should  rise 
materially,  he  could  raise  animalcules,  and  collect  the  shells,  and 
sell  them  at  a  profit  for  polishing  powder.  He  has  actually  ob- 
tained several  pounds  by  rearing  the  animalcules.  We  may 
have  occasion  to  notice  again  deposits  of  these  shells  in  Germany 

Were  all  the  monuments  of  olden  time. 

Egypt's  gray  piles  of  hieroglyphic  grandeur, 

That  have  survived  the  language  which  they  speak, 

Preserving  its  dead  emblems  to  the  eye, 

Yet  hiding  from  the  mind  what  these  reveal ; 

Her  pyramids  would  be  mere  pinnacles, 

Her  giant  statues,  wrought  from  rocks  of  granite, 

But  puny  ornaments  for  such  a  pile 

As  this  stupendous  mound  of  catacombs." — MONTGOMERY. 

What  is  said  of  animalcules  ?  what  of  their  shells  ?  What  is  silicious  marl  I 
What  is  said  of  the  fecundity  of  animalcules  ?  What  is  the  thickness  of  their 
deposits  in  Germany  ? 


80  ORGANIC    AGENCIES. 

of  the  thickness  of  fourteen  and  twenty-eight  feet,  and  to  describe 
some  as  existing  in  this  country. 

On  account  of  the  great  extent  of  silicious  deposits  known  to 
have  originated  from  this  source,  some  geologists  have  been  in- 
clined to  believe  that  most  of  the  silicious  strata  in  the  crust  of 
the  earth  once  constituted  the  shells  of  animalcules. 

Other  species  have  shells  composed  of  iron  rust,  and  much  of 
the  iron  scum,  which  may  be  seen  floating  on  water,  consists  of 
animalcules. 

This  class  of  animals  is  not  limited  to  fresh- water  deposits,  but 
many  kinds  exist  in  the  sea,  and  fossil  species  abound  in  some 
marine  deposits,  as  in  the  chalk  of  England. 

SECTION  III.— SHELLS. 

Another  organic  source  of  rocky  strata  is  to  be  found  in  the 
vast  quantities  of  the  shells  of  mollusca  and  of  the  crustaceous 
coverings  of  other  marine  animals,  which  are  most  abundant  in 
some  parts  of  the  tropical  seas.  In  such  regions  the  sand  of 
beaches  is  often  seen  to  be  composed  of  the  comminuted  calca- 
reous fragments.  So  in  the  ancient  palaeozoic  rocks  of  Lake 
Champlain,  we  find  entire  ledges  composed  of  pieces  of  corals 
and  shells.  It  is  probable  that  many  beds  of  crystalline  marble 
were  originally  composed  of  such  materials,  and  have  been  sub- 
sequently altered  by  igneous  agency. 

SECTION  IV.— PLANTS. 

Plants  are  well  known  to  form  deposits  of  vegetable  matter. 
From  their  complete  decay  results  vegetable  mold,  the  partic- 
ular consideration  of  which  belongs  to  agricultural  geology. 
While  many  quickly  perish,  others  are  more  enduring,  and  form 
accumulations  of  muck,  peat,  and  drift-wood.  Peat  results  chief- 
ly from  the  partial  decay  of  mosses,  especially  Sphagnum,  which 
constantly  grows  as  the  older  portions  decay.  Since,  however, 
in  hot  climates  the  decay  of  plants  is  rapid  and  complete,  when 

What  Is  said  of  iron  scum  ?  What  kinds  of  water  are  inhabited  by  animal- 
cules ?  What  is  said  of  the  agency  of  mollusca  ?  What  is  the  origin  of  veg- 
etable mold  ?  of  peat  ? 


AGENCY   OF    PLANTS.  81 

exposed  to  atmospheric  agency,  beds  of  peat  are  found  only  in 
cold  cjuntiies. 

Immense  rafts  of  drift-wood  are  well  known  to  accumulate  in 
the  lower  part  of  the  rivers  of  this  continent. 

The  Atchafalaya  is  supposed  to  have  been  formerly  the  chan- 
nel of  Red  River,  but  is  now  an  arm  of  the  Mississippi.  Some 
obstruction  occurred,  and  a  mass  of  timber  accumulated,  which 
was  called  "the  raft."  After  38  years,  in  1816,  ifwas  10  miles 
long,  220  yards  wide,  and  8  feet  thick.  The  Washita  was  de- 
scribed in  1804  as  covered  for  50  miles  with  a  raft,  on  which  all 
the  plants  of  the  forest,  except  large  trees,  were  growing.  Im- 
mense deposits  of  drift-wood  occur  at  the  mouth  of  the  Missis- 
sippi. 

In  a  few  cases,  as  in  Maine  and  Louisiana,  the  process  by 
which  drift-wood  may  be  converted  into  coal  has  been  seen  in 
its  incipient  stages.  Facts  of  this  kind  are  of  great  interest  as 
illustrating  the  origin  of  the  immense  beds  of  coal  in  the  carbo- 
niferous formations. 

Describe  the  raft  in  the  Atchafalaya;  in  the  Washita.  What  do  these  facts 
illustrate  ? 

D2 


PART  II. 


PRINCIPLES  OF  PALAEONTOLOGY. 

PALEONTOLOGY  treats  of  the  remains  of  animals  and  plants, 
which  hare  been  buried  in  the  strata  during  former  periods  of 
the  earth's  history. 


CHAPTER  I. 

PRINCIPLES  OF  ZOOLOGY  WHICH  RELATE  TO  FOSSILS. 

A  MINUTE  practical  knowledge  of  the  natural  history  and  anat- 
omy of  the  numerous  tribes  of  animals  and  plants  is  essential  in 
the  investigations  of  this  subject ;  but  it  requires  the  devotion  of 
a  lifetime  to  attain  this  knowledge  in  any  one  of  the  numerous 
sciences  which  treat  of  animals  and  plants.  The  geologist,  there- 
fore, after  becoming  familiar  with  the  outlines  of  these  sciences, 
contents  himself  with  depending  on  the  aid  of  zoologists  and  bot- 
anists in  determining  the  character  and  habits  of  extinct  species, 

SECTION  I.— CLASSIFICATION  OF  THE  ANIMAL  KINGDOM. 

We  subjoin  a  brief  outline  of  the  classification  of  the  animal 
kingdom,  as  indispensable  even  to  the  mere  reader  of  geology. 
About  150,000  species  of  animals  (of  which  two  thirds  are  in- 
sects) and  100,000  species  of  plants  are  known  to  naturalists. 
The  object  of  classification  is  not  merely  to  aid  the  memory  in 
the  knowledge  of  such  a  multitude  of  objects,  but  also  to  exhibit 

Of  what  does  Palaeontology  treat?  How  does  the  geologist  ascertain  the 
character  and  habits  of  extinct  species  ?  What  is  the  number  of  known  spe- 
cies of  animals  and  of  plants  ?  What  is  the  basis  of  the  classification  of  ani- 
mals? 


DIVISION    OP    THE    ANIMAL    KINGDOM.  83 

\he  natural  relations  of  affinity,  which  constitute  the  Divine  plan 
of  their  creation. 

The  animal  kingdom  is  divided  into  the  following  five  grand 
divisions,  which  are  characterized  primarily  by  peculiarities  of 
the  nervous  system.  This  part  is  the  most  important  and  distin- 
guishing feature  of  animals,  and  is  therefore  the  most  suitable 
basis  of  primary  divisions. 

I.  Vertebrala. — This  division  comprises  the  highest  orders  of 
animals,  with  man  at  the  head.     The  nervous  system  consists  of 
a  brain  and  spinal  cord,  from  which  branches  are  given  off  rami- 
fying indefinitely  through  the  body.     There  is  also  a  sympathetic 
system  of  nerves,  which  are  the  source  of  the  involuntary  motions, 
as  the  beating  of  the  heart,  and  which  originate  from  several  cen- 
ters in  the  body.     The  vertebrata,  also,  are  characterized  by  the 
possession  of  a  skeleton,  consisting  of  bones,  which,  unlike  the 
hard  parts  of  other  animals,  grow  and  are  continually  nourished 
by  the  circulation  of  the  blood.     The  organs  of  the  five  senses  are 
manifest  in  all  of  them,  and  four  of  the  senses  have  a  distinct  ap- 
paratus placed  in  the  cavities  of  the  face.     Examples  of  this  divi- 
sion are  the  warm-blooded  quadrupeds,  birds,  reptiles,  and  fishes. 
The  name  is  derived  from  the  vertebra  or  spine.     Their  fossil  re- 
mains, although  far  less  common  than  shells  in  the  strata,  lead  to 
very  interesting  and  important  conclusions  respecting  the  condi- 
tion of  the  surface  of  the  earth  during  the  periods  of  their  exist- 
ence. 

II.  Articulata. — The  nervous  system  in  this  division  consists 
of  nervous  centers  arranged  in  two  parallel  lines  along  the  length 
of  the  body,  the  anterior  one  in  the  head  being  the  larger.     These 
centers  send  out  nerves,  and  may  be  regarded  as  so  many  brains, 
the  number  of  which  is  inversely  proportioned  to  the  activity  and 
intelligence  of  the  animals.     In  this  division  we  find  an  external 
frame-work  of  jointed  rings.     Insects,  spiders,  crabs,  barnacles, 

What  is  said  of  the  nervous  system  of  the  vertebrata  ?  of  their  skeletons  ? 
of  their  senses  ?  What  examples  are  mentioned  ?  What  is  said  of  the  nerv- 
ons  system  of  the  articulata?  of  their  frame- work?  What  examples  are  men 
tioned  ? 


84     PRINCIPLES    OF    ZOOLOGY    WHICH    RELATE    TO    FOSSiLS. 

and  worms  are  examples  of  this  division.  The  name  is  derived 
from  articulus,  a  joint.  The  astonishing  number  of  individuals, 
their  direct  or  indirect  agency  on  vegetation  and  on  other  animals, 
render  the  study  of  them  one  of  the  most  important  branches  of 
Zoology.  But,  with  the  exception  of  the  Crustacea,  compara- 
tively fsw  relics  exist  in  a  fossil  state. 

III.  Mollusca. — In  the  mollusca  the  nervous  system  consists 
3f  several  irregularly-scattered  masses,  of  which  one  around  the 
throat  is  the  largest.     Most  of  these  animals  are  covered  with 
snells.     The  study  of  their  shells  belongs  to  the  science  ofconcfwl- 
ogy,  a  subject  which  is  of  the  highest  importance  to  the  geologist, 
for  the  great  majority  of  the  fossils,  by  means  of  which  the  age  of 
the  geological  formations  is  ascertained,  are  shells.     The  study  of 
shells  becomes,  therefore,  indirectly  of  great  economical  import- 
ance.    Thus,  inspection  of  the  shells  in  the  rocks  of  New  York 
shows  the  geologist  that  the  expectation  of  finding  coal  in  them, 
or  in  any  rocks  associated  with  them,  is  utterly  futile.     Univalve 
or  bivalve  shells  are  those  which  are  composed,  the  former  of 
one,  and  the  latter  of  two  principal  pieces.     Of  the  univalve 
shells,  some  are  divided  by  partitions  into  several   chambers, 
which  are  air-tight,  and  serve  as  a  float  to  the  animal.     At  the 
present  time  these  are  not  numerous,  but  in  former  geological 
epochs  they  were  very  abundant.     They  belong  to  the  class  of 
cephalopods  (see  table  opposite).     The  multivalve  shells  (those- 
which  are  composed  of  more  than  two  pieces),  for  the  most  part, 
do  not,  however,  belong  to  this  division  of  animals,  but  to  the  cir- 
rhopods,  a  class  of  articulated  animals. 

IV.  Nematoneura. — In  this  division  the  nervous  system  is  less 
fully  developed.     It  consists  of  filaments  of  nervous  matter,  with 
indistinct  masses  or  centers  in  a  few  of  them.     Examples  are 
sea-stars,  many  intestinal  worms,  and  some  animalcules,  and  a 
few  minute  marine  animals  allied  to  the  coral  polypes.     The 

What  is  said  of  their  numbers  ?  What  is  said  of  the  nervous  system  of  mol- 
lusca? of  their  shells?  What  is  said  of  the  importance  of  conchology?  What 
are  univalve  and  bivalve  shells  ?  What  is  said  of  chambered  shells  ?  What 
H  said  of  multivalve  shells  ?  What  is  said  of  the  nematoneura  ? 


DIVISION    OP   THE    ANIMAL   KINGDOM. 


Classes  of  the  Animal  Kingdom. 


CLASSES.                EXAMPLES. 

^    f  VIT  Iparons,  sailing  (    Respiration  aerial,    f 
p,    I          their  young.         )           with  lungs.           |   Warm 

Mammalia. 

' 

1  J        r         blood' 

Birds. 

£    ]           Oviparous.          1                                     >   Cold 

Reptiles. 

W    [                                      j   Respiration  aquatic,  <   blood. 
>    I                                     V.          with  gills.           £ 

Fishes. 

. 

(With  6  legs.        Insects. 

Beetles. 
Flies. 

j 

\  Myriapods. 

J.6^S«                  / 

Centipedes. 

}< 

8  legs.              Arachnidans. 

Spiders. 
Scorpions. 

H 

Aquatic         <     10  or  14  legs.        Crustaceans. 

Lobsters. 
Crabs. 

«*! 

/              p,               t  Cirrkopods.           Barnacles. 
Red     (  Aquatic  or    <            /                <                             5  Earthworms 
>lood.  J  Terrestrial.  \                             (  Annelidans.        \  Leeches. 

With  a  distinct  j      Naked,  or  with  a 

*  Hyatea!b* 

head.            j        univalve  shell. 

Jrteropods.           ^  gjucrg< 

l\                ( 

Oasteropods.      |  Cowries. 

g           .  ,            ..              With  a  bivalve 

'  Brachiopods.          Terebratula. 

[                             1             Naked. 

Tunicata.              Ascidia. 

T  Marine.                                                           Echinodermata.     Sea  stars. 

T                            (  Cavitary  in- 
^                                                                                Coslelmintha.      ^      testinal 

(      worms. 

z  !  Parasitic  and  Aquatic.                                                           C  Parasites  on 
H  1                                                                       i  Epizoa.              <      fishes  and 

I 

(      on  crabs. 

£ 
Aquatic. 

Rotifera.             J  ^^c^Ss. 

[^Marine.                                                           Bryozoa.               Flustra. 

• 

Parenchyma- 

Parasitic. 

Sterelmintha. 

tous  intesti- 

nal  worms. 

Sunfish  and 

J 

Marine. 

Acalephee. 

Portuguese 

g 

man-of-war. 

2  ' 

o 

Animalcules 

S 

Aquatic. 

Polygattrica. 

with  many 

stomachs. 

c 

Animals 

Marine.                                                         <  Polypi. 

which  form 

I 

corals. 

86      PRINCIPLES   OF    ZOOLOGY    WHICH   RELATE   TO    FOSSILS. 

name  is  derived  from  the  Greek  words  vr\]ia  and  vevpa,  thread 
nerve. 

V.  Acrita. — In  these  animals  no  nervous  system  has  been  rec 
ognized,  and  their  bodies  consist  of  fleshy  or  gelatinous  masses, 
without  distinct  organs  of  digestion  or  motion.  They  may  be  cut 
in  pieces  with  impunity,  each  part  becoming  an  entire  animal, 
and  they  naturally  increase  by  spontaneous  division,  as  well  as 
by  offshoots  and  by  eggs.  Examples  are  the  animals  which  se 
crete  the  well-known  coral  structures,  some  animalcules,  sun- 
fishes,  &c.  The  name  is  derived  from  two  Greek  words,  a  and 
%piv(>),  indiscernible,  because  no  nerves  have  yet  been  found  in 
them. 

SECTION  IL— ORIGIN  AND  NATURE  OF  SPECIES. 

This  subject  involves  two  questions —  WTien  and  how  does  Cre- 
ative Power  introduce  new  species  1 

I.  When  are  species  introduced  ?  Geology  shows  us  that  they 
have  been  introduced  from  time  to  time  during  long  periods. 
Some  suppose  that  the  introduction  of  species  forms  a  part  of 
the  present  order  of  things.  But  if  it  would  be  difficult  to  learn 
the  precise  time  when  species  die  out,  much  more  is  it  to  determ- 
ine the  year  or  the  century  of  their  introduction.  If  some  are 
now  introduced  from  time  to  time,  it  is  probable  that  such  an 
event  is  not  more  frequent  than  the  extinction  of  others,  and  as 
it  would  be  more  common  among  the  smaller  and  inferior  tribes, 
on  account  of  their  numerical  preponderance,  it  might  occur  fre- 
quently, without  being  demonstrable.  When  species  before  un- 
known are  discovered,  we  know  not  whether  some  of  them  have 
been  created  within  a  few  years,  or  whether  they  have  been  over- 
looked. It  is  only  when  the  view  is  extended  through  periods 
in  which  centuries  dwindle,  like  terrestrial  distances  seen  from 
the  planetary  spaces,  that  we  may  speak  with  confidence  of  the 
gradual  introduction  and  extinction  of  species. 

What  is  said  of  the  acrita?  What  questions  relate  to  the  origin  of  species? 
What  does  geology  show  of  the  time  of  their  introduction  ?  What  is  said  of 
the  question  of  their  introduction  during  modern  times  ? 


INTRODUCTION    OF    SPECIES.  87 

II.  How  are  species  introduced  ?  This  question  has  been  much 
tfiscussed,  and  some  of  the  theories  have  been  supposed  to  con- 
flict with  the  great  truth  of  religion,  that  species  are  created  by 
a  Being  of  infinite  intelligence  and  goodness.  Some  writers, 
therefore,  with  more  zeal  than  knowledge,  have  made  upon  these 
theories  attacks  which  are  too  absurd  to  engage  the  attention  of 
sober  science.  Whether  species  are  introduced  by  a  special  act 
of  creation,  or  whether  the  actions  of  the  Supreme  Being,  in  this 
as  in  other  events  of  nature,  have  such  a  uniformity  and  such  fix- 
ed principles  that  we  may  call  them  laws  of  nature,  are  questions 
which  should  disturb  no  man's  religious  belief.  Our  limits,  how- 
ever, will  not  permit  us  to  discuss  the  theories,  and  we  can  merely 
give  a  synopsis  of  them  without  adducing  any  of  the  facts  with 
which  they  are  connected. 

1.  One  theory  supposes  that  species  are  introduced  by  a  direct 
creative  agency,  which  is  of  the  nature  of  a  miracle  ;  that  is,  can 
not  be  referred  to  any  uniform  course  of  nature. 

2.  Another  theory  is  that  of  transmutation,  which  supposes  that 
beings  of  the  most  simple  organization  having  somehow  come 
into  existence,  the  more  complex  and  the  higher  orders  of  ani- 
mals have  originated  in  them  by  a  gradual  increase  in  the  com- 
plexity of  their  structure.     Of  this  theory  there  have  been  various 
modifications.     It  was  supposed  by  Buffon,  originally,  that  there 
were  elementary  particles  of  living  matter,  viz.,  animalcules, 
whose  fortuitous  aggregation  formed  larger  animals,  which  are 
therefore  only  heaps  of  animalcules.     Lamark  supposed  that  ani 
malcules  are  elementary  particles  of  living  matter,  but  that  the 
larger  animals  were  formed  from  them  by  the  process  of  appe- 
tency, which  we  shall  presently  notice.     The  basis  of  this  theory 
and  the  basis  and  superstructure  of  Buffon's  theory,  were  over 
thrown  by  those  naturalists  who  discovered  that  animalcules  have 
a  very  complicated  organization.     The  doctrine  of  appetency 
supposed  that  new  organs  are  formed  in  animals  before  destitute 

What  is  said  of  discussion  on  the  manner  of  introduction  ?  What  is  the  first 
theory  ?  What  is  the  theory  of  transmutation  ?  What  was  Buffon's  opinion  f 
Lamark's  ?  What  is  said  of  the  d  »ctrine  of  appetency  ? 


88       PRINCIPLES    OF    ZOOLOGY    WHICH    RELATE    TO    FOSSILS. 

of  them,  by  the  existence  of  desires  in  the  animal  constantly  tend- 
ing in  a  given  direction.  Thus  the  desire  of  masticating  food 
produced  teeth,  the  desire  of  handling  made  hands  and  fingers 
grow,  &c.  This  seems  sufficiently  absurd,  and  those  who  have 
adopted  the  theory  of  transmutation  have  generally  detached  it 
from  this  absurdity,  and  not  attempted  to  explain  how  the  pro- 
cess of  transmutation  goes  on. 

It  was  never  supposed  that  the  process  of  transmutation  was 
so  rapid  that  any  perceptible  progress  could  be  made  within  the 
limits  of  human  observation.  But  the  long  periods  of  geology 
were  supposed  to  afford  ample  scope  ;  and  the  idea  formerly  pre- 
vailing, that  species  which  first  existed  were  of  the  simplest  forms, 
and  that  the  more  complex  were  gradually  introduced,  seemed  to 
corroborate  the  theory.  The  geologist,  however,  finds  that  some 
of  the  higher  orders  were  among  the  early  inhabitants  of  the 
globe,  and  that  while  in  some  portions  of  the  animal  kingdom 
there  has  been  a  gradual  introduction  of  the  more  complex  forms, 
in  others  the  process  has  been  retrograde.  This  theory  appears 
to  have  been  suggested  by  the  fact  that  in  many  groups  of  spe- 
cies there  is  a  gradual  passage  from  one  to  another,  without  any 
distinct  line  of  division  between  them.  But  gradation  is  not  prog- 
ress, and  transmutation,  therefore,  is  not  logically  inferred. 

3.  Another  theory  is  that  of  equivocal  generation,  which  is  not 
exclusively  applied  to  the  introduction  of  species,  but  which  sup 
poses  that  individuals  of  species,  which  may  or  may  not  have  pre- 
existed, may  be  generated  by  circumstances  supposed  to  be  fa- 
vorable to  such  a  process.  It  once  had  a  wide  application,  and 
bees,  flies,  snakes,  weeds,  mushrooms,  &c.,  were  supposed  to  be 
formed  in  this  manner.  The  substitution  of  the  rigid  and  exact 
observations  which  characterize  modern  science,  in  place  of  the 
idle  speculations  of  former  days,  and  especially  the  use  of  the 
microscope,  have  shown  the  relation  of  parent  and  offspring  to 
exist  in  most  of  these  cases,  and  the  unexplored  portions  of  na- 
dure  to  which  this  theory  is  applied  are  greatly  reduced.  The 

What  is  said  for  and  against  the  theory  of  transmutation  ?     What  is  said  of 
the  theory  of  equivocal  generation  ?  of  the  vitality  of  seeds  and  of  animalcules  ? 


NATURE    OF    SPECIES.  89 

inquiries  on  this  subject,  without  confirming  this  theory,  do,  how 
ever,  extend  our  views  in  respect  to  the  vitality  of  seeds,  and  of 
the  inferior  forms  of  animal  life.  Seeds  which  have  been  dor- 
mant for  centuries  have  been  made  to  grow,  and  every  one  knows 
that  the  clearing  of  wood-land  is  often  followed  by  a  different 
growth  of  timber,  whose  seeds  have  been  for  centuries  in  the 
shade  of  the  forest.  Animalcules  are  known  to  exist  for  years 
without  manifestations  of  life,  in  a  state  of  dry  powder,  the  sport 
of  the  winds,  and  on  application  of  moisture  have  revived. 

We  conclude,  therefore,  that  the  first  hypothesis  is  correct,  viz., 
that  each  species  is  introduced  by  the  special  direct  agency  of 
the  Creator. 

4.  We  have  yet  to  inquire  into  the  question  of  the  unity  or  plu- 
rality of  the  origin  of  species.  A  variety  of  considerations,  which 
are  drawn  from  the  geographical  distribution  of  the  species,  and 
which  are  more  properly  described  in  zoological  works,  lead  to 
the  conclusion  that  each  species  was  originally  created  by  the 
introduction  of  many  individuals,  in  some  cases  in  distant  regions, 
but  more  frequently  in  one  region  of  greater  or  less  extent,  and 
that  they  were,  with  few  exceptions,  created  in  the  same  coun 
tries  which  they  now  inhabit. 

Of  the  nature  of  the  process  by  which  the  originals  of  the  spe- 
cies were  created,  science  is  entirely  ignorant. 

III.  Nature  of  Species. — The  original  individuals  of  a  species 
appear  to  have  had  the  same  peculiarities  which  now  character- 
ize races  and  varieties.  The  gradation  from  one  species  to  an- 
other was  original  in  their  first  creation.  Species  are,  therefore, 
of  the  same  nature  as  genera;  that  is,  they  can  be  defined  only 
as  groups  collected  around  types,  and  they  are  often  destitute  of 
well-defined  limits.  Gradation  is  thus  more  logically  accoutted 
for  by  original  creation  than  by  transmutation. 

What  is  said  on  the  question  of  unity  or  plurality  of  origin?  What  is  said 
of  the  process  of  creation  ?  of  the  nature  of  epecies  I 


90       PRINCIPLES    OF    ZOOLOGY    WHICH    RELATE    TO    FOSSILS. 
SECTION  III.— DURATION  OF  SPECIES. 

I.  Means  of  their  Preservation. — Nature  has  not  left  the  indi- 
viduals of  species  without  many  safeguards  against  the  dangers 
to  which  they  are  exposed.     Yet  multitudes  of  seeds  perish  with- 
out germination,  and  the  greater  portion  of  the  animal  kingdom 
perish  by  violence  long  before  reaching  the  limit  of  which  their 
life  is  susceptible,  so  that  a  "  natural  death"  is  rather  the  excep- 
tion than  the  rule  in  nature.     But  the  life  of  a  species,  if  we  may 
so  speak,  is  far  more  carefully  guarded.     To  every  species  is 
given  a  degree  of  fecundity  far  beyond  that  which  would  be  re 
quired  for  its  perpetuity,  if  not  exposed  to  occasional  accidents 
and  disastrous  seasons ;  while,  for  the  excessive  multiplication 
consequent  on  a  favorable  season,  checks  are  provided  in  the  lim- 
ited supply  of  nourishment,  and  in  the  enemies  which  increase 
by  this  increase  of  their  prey.     Thus  individuals  may  perish  in 
countless  myriads,  but  the  species  endure  from  age  to  age,  and 
not  a  few  of  the  feeblest  and  most  minute  species  have  existed 
many  times  longer  than  man  himself. 

II.  Causes  of  extreme  Longevity. — Without  the  aid  of  geology, 
zoology  can  give  us  no  information  on  the  duration  of  species, 
for,  in  the  rare  cases  where  the  species  has  become  extinct  within 
the  historical  period,  it  teaches  nothing  definitely  respecting  their 
origin.     Happily,  however,  the  case  of  some  species  now  in  ex 
istence,  and  whose  remains  are  found  in  some  of  the  tertiary 
strata,  is  full  of  instruction.     Of  the  twelve  hundred  and  thirty- 
eight  species  of  shells  which  existed  in  the  earliest  of  the  tertiary 
periods,  forty-two  are  supposed  to  be  identical  with  living  spe- 
cies.    If,  now,  we  can  satisfactorily  account  for  their  longevity,  or 
even  discover  any  condition  connected  with  it,  we  shall  obtain  a 
view  of  principles  which  are  highly  instructive  on  this  subject. 

Some  of  the  species  which  have  thus  survived  the  changes  on 
the  earth's  surface,  that  have  proved  fatal  to  most  of  their  former 
cotemporaries,  have  a  wide  geographical  distribution.  This  "in- 
dicates a  capacity  of  enduring  a  variety  of  external  circumstan- 

What  is  said  of  the  means  of  their  preservation  ?  What  examples  of  ex- 
treme longevity  of  species?  of  the  distribution  of  such  species? 


LONGEVITY    OF    SPECIES.  9] 

ces,  and  may  enable  a  species  to  survive  considerable  changes 
of  climate,  and  other  revolutions  of  the  earth's  surface."  —  Lyell. 
Lucina  divaricata,  which  was  introduced  in  the  tertiary  periods, 
now  inhabits  all  our  coast  south  of  Long  Island,  the  West  Indies, 
and  the  Mediterranean.  Saxicava  rugosa,  now  living  on  the 
shores  of  Europe  and  America,  is  found  in  the  pleistocene  de- 
posits of  both  countries,  and  as  far  back  as  the  eocene  in  Europe. 

If  thus  a  species  is  capable  of  enduring  extremes  of  climate  in 
a  wide  geographical  range,  the  probability  that  it  is  a  long-lived 
species  may  be  inferred.  Among  fossil  species,  therefore,  those 
which  occur  in  several  successive  formations  are  the  more  likely 
to  be  found  in  the  strata  of  distant  countries,  or  conversely,  those 
which  are  known  to  have  this  wide  geographical  range  are  less 
likely  to  be  restricted  to  a  single  formation. 

Others  which  have  also  survived  the  three  great  tertiary  peri- 
ods, or,  in  the  language  of  Sir  Charles  Lyell,  "  have,  like  Nestor, 
survived  three  generations,"  are  species  which,  living  in  deep 
water,  find  a  uniformity  of  temperature  and  of  other  conditions 
that  do  not  exist  at  the  surface.  Such  frequently  have,  from  this 
cause  rather  than  from  any  innate  capacity  of  endurance,  a  wide 
geographical  range. 

Others,  again,  are  species  which  have  gradually  migrated  into 
warmer  latitudes,  as  the  climate  has  gradually  become  colder. 
Several  species  of  shells,  which  are  now  found  only  in  a  fossil 
state  in  Middle  Europe,  are  living  within  the  tropics.  Hence 
we  should  derive  a  caution  in  inferring  the  cotemporaneousness 
of  distant  formations  from  the  identity  of  a  few  species,  for  it  is 
possible  that  some  of  these  formations  may  have  had  the  same 
climate  at  periods  which,  although  not  far  distant  on  the  geolog- 
ical scale,  may  yet  have  been  by  no  means  cotemporaneous. 

III.  Comparative  Longevity  of  different  classes  of  Animals. — The  * 
species  of  some  classes  are  much  more  enduring  than  of  others. 
Of  the  mammals  no  living  species  can  be  traced  further  back 

What  inferences  may  be  made  from  their  wide  distribution  ?  What  is  said 
of  species  that  live  in  deep«water  ?  of  the  migration  of  species  ?  What  is  said 
of  the  longevity  of  species  of  mammals  ? 


92       PRINCIPLES    OF    ZOOLOGY    WHICH    RELATE    TO    FOSSILS. 

than  the  most  recent  of  the  tertiary  periods.  The  fossil  remains 
of  birds  are  perhaps  too  few  to  warrant  any  positive  generaliza- 
tions, but  those  which  have  been  found  belonging  to  former  peri- 
ods are  distinct  from  any  now  living.  Of  fishes  which  have  been 
found  in  greater  or  less  numbers  in  nearly  all  the  fossiliferous 
rocks,  the  same  species  is  scarcely  ever  found  in  two  successive 
formations.  They  are,  therefore,  the  most  serviceable  in  determ- 
ining the  cotemporaneousness  of  distant  formations. 

Most,  perhaps  all  of  the  species  of  fresh-water  mollusca,  which 
were  introduced  in  the  United  States  during  the  pleistocene  pe- 
riod, continue  at  the  present  time.  But  the  mastodon,  megathe- 
rium, acd  other  quadrupeds  of  that  period,  are  all  extinct,  and 
their  places  have  been  filled  by  other  species.  In  general,  the 
species  of  mollusca  have  a  greater  longevity  than  the  verlebrata. 

SECTION  IV.— EXTINCTION  OF  SPECIES. 

Since  the  vast  majority  of  the  species,  and  many  entire  genera 
and  families,  whose  remains  are  found  in  a  fossil  state,  hare  long 
since  become  extinct,  any  facts  of  a  similar  character  within  the 
historical  period  become  invested  with  extraordinary  interest. 
Of  so  recent  a  date,  however,  is  zoological  science,  to  which  alone 
we  can  look  for  any  information  respecting  the  countless  host  of 
small  species  which  people  the  air  and  the  waters,  that  the  facts 
are  few  and  relate  only  to  the  larger  species.  The  extinction  of 
the  fossil  species  was  owing  primarily  to  the  constitution  of  the 
species,  and  partly  to  gradual  changes  of  climate,  aided  by  muta- 
tions in  the  distribution  of  land  and  water.  Since  the  existence 
of  man,  his  agency  has  had  a  marked  effect  in  the  more  or  less 
complete  extermination  of  some  species,  and  in  the  increased  de- 
velopment of  others,  to  subserve  his  purposes.  Many  quadru- 
peds, as  the  beaver,  wolf,  bear,  &c.,  are  now  extinct  in  Great 
Britain.  The  perseverance  with  which  the  fur  trade  is  carried 
on  is  rapidly  tending  to  the  extermination  of  many  species. 

"  Immediately  after  South  Georgia  was  explored  by  Captain 

What  is  said  of  birds  ?  of  fishes  1  of  mollusca  as,  compared  with  vertebrate! 
To  what  was  the  extinction  of  the  fossil  species  owing  ? 


EXTINCTION    OF    SPECIES.  93 

Cook,  in  1771,  the  Americans  commenced  carrying  seal-skins  to 
China,  where  they  obtained  most  exorbitant  prices.  One  million 
two  hundred  thousand  skins  have  been  taken  from  that  island 
alone  since  that  period,  and  nearly  an  equal  number  from  the 
island  of  Desolation  !  The  numbers  of  the  fur-seals  killed  in  the 
South  Shetland  Isles,  in  1821  and  1822,  amounted  to  three  hund- 
red and  twenty  thousand.  This  valuable  animal  is  now  almost 
extinct  in  all  these  islands." 

"  An  extraordinary  bird,  a  native  of  New  Zealand,  of  which 
but  few  living  individuals  arc  known  to  naturalists,  appears  to  be 
on  the  point  of  extinction ;  it  is  the  Apteryx  australis."  "  This 
bird  is  of  a  grayish  brown  color,  and  has  neither  wings  nor  tail." 
"  The  Dodo  was  a  bird  of  the  gallinaceous  tribe,  larger  than  a 
turkey,  which  abounded  in  the  Mauritius  and  adjacent  islands, 
when  those  countries  were  first  colonized  by  the  Dutch,  about 
two  centuries  ago.  This  bird  formed  the  principal  food  of  the 
inhabitants,  but  was  found  to  be  incapable  of  domestication,  and 
its  numbers  therefore  soon  became  sensibly  diminished.  Stuffed 
specimens  were  preserved  in  the  museums  of  Europe,  and  paint- 
ings of  the  living  animal  are  still  extant  in  the  Ashmolean  Muse- 
um at  Oxford,  and  in  the  British  Museum.  But  the  Dodo  is  now 
extinct — it  is  no  longer  to  be  found  in  the  isles  where  it  once 
flourished  ;  and  all  the  stuffed  specimens  are  destroyed.  The 
only  relics  that  remain  are  the  head  and  foot  of  an  individual  in 
the  Ashmolean,  and  the  leg  of  another  in  the  British  Museum. 
To  render  this  illustration  complete,  the  bones  of  the  Dodo  have 
been  found  in  a  tufaceous  deposit  beneath  a  bed  of  lava,  in  the 
Isle  of  France  ;  so  that  if  the  remains  of  the  recent  bird  alluded 
to  had  not  been  preserved,  these  fossil  relics  would  have  con- 
stituted the  only  proof  that  such  a  creature  had  ever  existed  on 
our  planet." — Mantell. 

In  Ireland  a  large  species  of  elk  became  extinct  probably  not 
long  after  the  island  was  inhabited  by  man. 

"  Its  remains  commonly  occur  in  the  beds  of  marl  beneath  the 
peat-bogs."  "  In  Curragh,  immense  quantities  of  the  bones  of 
the  elk  lie  within  a  small  space,  as  if  the  animals  had  assembled 
in  a  herd  ;  the  skeletons  appear  to  be  entire,  and  the  nose  is  ele- 
vated, the  antlers  being  thrown  back  on  the  shoulders,  as  if  the 
creatures  had  sunk  in  a  morass,  and  been  suffocated."  "  The 
skeleton  is  upward  of  ten  feet  high  from  the  ground  to  the  high- 

What  is  said  of  human  agency  in  the  extinction  of  species  ?  What  is  said 
of  the  Irish  elk  ? 


94      PRINCIPLES    OF    ZOOLOGY    WHICH    RELATE    TO    FOSSILS. 

est  point  of  the  antlers,  which  are  palmated,  and  from  ten  to  four- 
teen from  one  extremity  to  the  other."  "  In  the  county  of  Cork, 
a  human  body  was  exhumed  from  a  wet  and  marshy  soil,  beneath 
a  bed  of  peat  eleven  feet  thick  ;  the  body  was  in  good  preserva- 
tion, and  enveloped  in  a  skin  covered  with  hair,  which  there  was 
every  reason  to  conclude  was  that  of  the  elk.  A  rib  of  the  elk 
has  also  been  found,  in  which  there  was  a  perforation  that  evi- 
dently had  been  formed  by  a  pointed  instrument  while  the  ani- 
mal was  alive,  for  there  is  an  effusion  of  callus  or  new  bony  mat- 
ter, which  could  not  have  resulted  from  something  remaining  in 
the  wound  for  a  considerable  period ;  such  an  effect,  indeed,  as 
would  be  produced  by  the  head  of  an  arrow  or  spear.  There  is, 
therefore,  presumptive  evidence  that  the  race  was  extirpated  by 
the  hunter-tribes  who  first  took  possession  of  the  British  Islands." 
— Mantell. 

But  the  most  remarkable  of  all  the  species  which  have  become 
extinct  within  the  historical  period  are  those  of  Dinornis,  a  genus 
of  birds,  some  of  which  were  of  enormous  size,  far  exceeding  the 
ostrich.  Their  bones  are  found  in  recent  deposits  in  New  Zea- 
land, and  the  natives  have  a  tradition  of  the  former  existence  of 
this  bird,  which  they  called  Moa.  It  was  allied  to  the  Apteryx 
in  its  characters,  being  without  wings.  The  thigh  bone  of  the 
larger  species  was  upward  of  two  feet  in  length.  Being  the 
only  land  animal  in  that  country  of  sufficient  size  to  furnish  food 
to  the  people,  it  was  probably  exterminated  by  the  early  inhab- 
itants. 

These  are  the  only  animals  which  are  known  to  have  become 
extinct  since  the  commencement  of  man's  existence.  Many 
which  flourished  during  the  periods  immediately  preceding  have 
since  become  extinct,  but  so  slow  are  the  changes  in  nature  and 
so  long  is  an  entire  period,  the  unit  in  geological  computation, 
that  it  is  not  easy  to  determine  whether  any  such  were  in  exist- 
ence in  the  earliest  days  of  our  race. 

SECTION  V.— GEOGRAPHICAL  DISTRIBUTION. 

The  geographical  distribution  of  animals  and  plants  is  a  sub- 
ject of  great  importance  in  its  application  to  geology.  Although 
the  subject  is  so  copious  in  its  details  that  it  can  never  be  ex- 

What  is  said  of  the  genus  Dinornis  ? 


DISTRIBUTION    OF    SPECIES.  95 

hausted,  a  few  outlines  may  be  sketched  as  sufficient  to  give 
some  general  view.  The  common  observer,  who  is  unaccus- 
tomed to  careful  discrimination  between  the  species,  especially 
of  small  animals  and  plants,  which  nearly  resemble  each  other, 
is  not  aware  of  the  great  difference  between  the  Fauna  and  Flora 
of  different  countries.  Thus  of  the  species  of  shells  in  the  West 
Indies,  probably  less  than  one  in  one  hundred  exists  in  the  New 
England  States.  The  native  quadrupeds  of  the  United  States 
are  specifically  distinct  from  those  of  Europe.  Of  the  countless 
hosts  of  insects,  few,  if  any,  are  common  to  both  sides  of  the 
ocean,  except  those  which  have  been  transported  by  human 
agency. 

The  distribution  of  the  species,  apart  from  the  influence  of 
human  agency,  depends  on  the  places  of  original  creation,  on 
climate,  and  on  station  or  the  kind  of  place  which  their  habits 
require.  Climate  and  station  have  influenced  distribution  in  twc 
ways ;  by  determining,  in  the  Divine  plan,  the  place  of  original 
creation,  and  by  restraining  subsequent  dispersion. 

I.  Places  of  Original  Creation. — A  few  species  appear  to  have 
been  originally  introduced  into  different  countries.     Thus  a  small 
snail,  Helix  pulchella,  is  aboriginal  in  both  Europe  and  the  Unit- 
ed States.     Fresh-water  fishes  of  the  same  species  inhabit  dis- 
tant rivers.     But  more  frequently  the  places  of  original  creation 
of  the  individuals  of  a  species  are  adjacent. 

II.  The  connection  between  climate  and  distribution  is  very  ob- 
vious.    Let  any  one  travel  a  thousand  miles  of  latitude,  and  he 
will  find  that  he  has  left  behind  him  a  great  majority  of  the  fa- 
miliar species.     Let  him  go  two  thousand  miles,  and  the  appear- 
ance of  a  single  species  which  he  has  been  accustomed  to  see 
will  be  an  era  in  his  wanderings.     Not  only  so,  but  there  will  be 
a  striking  difference  in  the  more  comprehensive  groups :  whole 
genera,  families,  or  even  orders  have  disappeared,  and  new  ones 

What  is  said  of  the  differences  in  the  animals  of  different  countries  ?  On 
what  does  the  distribution  of  species  depend  ?  In  what  ways  have  climate 
and  station  influenced  distribution  ?  What  is  said  of  the  places  cf  original 
creation  ?  of  the  connection  between  climate  and  distribution  ? 


96      PRINCIPLES    OF    ZOOLOGY   WHICH    RELATE    TO    FOSSILS. 

surround  him.  On  the  other  hand,  an  equal  change  of  longitude 
will  present  fewer  changes  in  the  more  comprehensive  groups, 
and  in  the  species,  which  changes  will  be  found  chiefly  depend- 
ent on  intervening  barriers  of  mountains,  water,  &c. 

In  some  cases  whole  tribes  of  animals  and  plants,  and  in  others 
the  individuals  of  particular  species  only  in  a  genus,  are  equally 
affected  by  climate. 

Thus  the  whole  tribe  of  palm-trees  and  many  families  of  shells, 
either  exclusively  or  with  the  exception  of  a  few  of  the  smaller 
and  less  characteristic  species,  such  as  the  cowry  family,  with 
their  richly- colored  and  highly-polished  shells,  are  found  in  great 
profusion  only  in  hot  climates.  The  oaks,  if  found  within  the 
tropics,  are  on  elevated  regions,  where  they  have  the  climate 
proper  to  a  higher  latitude.  Again,  there  are  some  genera  which 
exist  in  all  climates,  as  Helix  (snails),  but  are  represented  in 
each  climate  by  peculiar  species.  In  most  cases  there  exist  pe- 
culiarities by  which  the  experienced  naturalist  can  distinguish 
the  species  of  one  climate  from  those  of  another.  Rarely  the 
enme  species  exists  in  very  different  climates.  The  Lucina  di- 
va, ricata  mentioned  on  page  91,  and  a  few  others,  are  exceptions 
to  the  general  rule.  A  peculiar  class  of  examples  of  this  kind 
are  the  migrating  animals,  which  find  a  greater  uniformity  of 
climate  by  changing  their  abode  as  the  season  changes.  From 
these  facts  we  should  expect,  if  the  climate  had  ever  been  uni- 
form over  the  surface  of  the  earth,  that  species  would  have  had 
a  much  wider  geographical  range  than  at  present,  and  this  ap- 
pears to  have  been  the  fact  in  the  earliest  periods. 

III.  The  circumstances  of  station  restrain  the  dispersion  of 
species.  Bodies  of  water  interpose  an  obstacle  to  the  distribu- 
tion of  terrestrial  animals  ;  fresh  water  to  the  marine,  and  salt 
water  to  the  fresh  water  species.  Deserts  and  mountains  sepa- 
rate zoological  as  well  as  politM^l  provinces.  Islands  have  their 
peculiar  Fauna  and  Flora.  Some  species  can  exist  only  on  cer- 
tain geological  formations  ;  thus  the  larger  and  heavier  land-shells 
of  some  tropical  countries  exist  only  in  limestone  regions,  and 
the  land-shell?  of  this  country  are  far  more  abundant  in  such 
districts,  although  not  exclusively  confined  to  them.  Some  re- 

What  examples  are  mentioned  ?  In  what  ways  do  the  circumstances  of  sta- 
tion restrain  the  dispersion  of  species  ? 


STATION    OP    SPECIES.  97 

quire  dry  and  others  wet  land ;  some  pure,  and  others  impure 
water;  some  live  on  sand,  others  in  mud;  some  on  high  land, 
others  on  low  land ;  some  in  deep  water,  others  on  shore.  A 
few  species,  again,  can  accommodate  themselves  to  a  variety  of 
stations.  All  these  facts  it  is  the  business  of  the  zoologist  to  in 
vestigate,  and  on  him,  consequently,  the  geologist  is  dependent  for 
the  means  of  drawing  conclusions. 

Sometimes  there  is  a  peculiar  grouping  of  species ;  as  when  a 
river  flowing  into  an  estuary  mixes  terrestrial,  fresh  water,  and 
marine  species  in  the  same  deposit ;  or  when  beasts  of  prey  drag 
into  caves  the  carcasses  of  various  animals ;  or  when  the  hermit 
crabs,*  so  abundant  in  hot  climates,  and  with  amphibious  habits, 
occasionally  mingle  terrestrial  and  marine  shells  on  the  open 
coast  without  fluviatile  agency. 

In  the  application  of  these  general  facts  to  the  case  of  fossils 
of  extinct  species  in  older  formations,  no  universal  rule  can  be 
given  by  which  to  determine  whether  a  given  species  inhabited 
a  hot  climate  or  otherwise,  but  the  decision  must  depend  on  its 
zoological  affinities.  If  the  species  belongs  to  a  group  which  is 
found  exclusively  in  the  tropics,  the  probability  that  it  was  trop- 
ical will  be  very  strong ;  and  if  a  large  number  of  such  species 
are  found  in  the  same  formation  without  any  which  are  proper  to 
colder  climates,  the  conclusion  may  be  considered  certain.  If, 
however,  the  extinct  species  belong  to  a  group  which  is  univers- 
ally distributed,  and  if  it  has  none  of  the  distinctive  marks  of 
climate  on  it,  it  will  fail  of  establishing  any  conclusion  respecting 
the  climate. 

From  the  peculiarities  of  station  which  characterize  not  only 
species,  but  more  comprehensive  groups,  the  geologist  is  usually 
able  to  make  very  interesting  and  important  inferences  respecting 

*  Crabs,  whose  instinct  leads  them  invariably  to  enter  the  empty  shells  of 
dead  molluscs  for  the  protection  of  their  bodies,  that  are  not  sufficiently  pro- 
tected by  the  thin  crust  with  which  they  are  covered,  are  called  "hermit 
crabs." 

What  peculiar  groupings  of  species  are  mentioned  ?  What  is  said  of  infer- 
ences respecting  the  climates  inhabited  by  the  fossil  species  ?  What  infereu 
cei  respecting  the  geography  of  ancient  periods  ? 

E 


98      PRINCIPLES    OF    ZOOLOGY    WHICH    RELATE    TO    FOSSILS 

the  geography  of  a  region,  as  it  was  at  the  time  when  the  spe<.ol<ja 
now  extinct  was  in  existence. 

Fossil  shells  show  whether  the  deposit  was  made  in  fresh  or 
salt  water ;  or  if  species  of  both  fresh  and  salt  water  are  mingled, 
it  will  be  generally  inferred  that  the  deposit,  especially  if  the  lay- 
ers form  a  basin-shaped  depression,  was  made  in  an  estuary  into 
which  a  river  emptied.  The  depth  of  the  water  may  often  be 
inferred  from  the  genus  to  which  the  fossil  belongs.  The  char- 
acter of  the  shells  will  also  show  whether  it  was  a  sandy  or  a 
muddy  shore ;  in  this  particular,  however,  merely  confirming  the 
inferences  made  from  the  mineral  characters  of  the  strata.  Fos- 
sil plants  show  not  only  the  temperature  of  the  climate,  but  its 
humidity,  and  the  general  features  of  the  surface.  The  geological 
student  will  find  in  the  copious  details  of  zoology,  with  which  we 
are  not  here  concerned,  that  the  geological  inferences  are  as  full  of 
interest  as  are  the  zoological  premises  from  which  they  are  made. 

Terrestrial  animals  are,  for  the  most  part,  distributed  in  the  fol 
lowing  manner.  Commencing  with  the  Arctic  regions,  the  same 
species  generally  occur  in  both  hemispheres.  In  the  temperate 
regions,  most  of  the  species  of  North  America,  Europe,  and  Asia 
are  peculiar  to  each  of  these  regions,  but  are  very  similar  to  each 
other.  In  the  tropical  regions  the  differences  are  greater.  IP 
the  southern  extremities  of  the  great  bodies  of  land,  New  Hol- 
land, South  Africa,  and  Patagonia,  the  differences  are  greatest. 

The  details  of  the  subject  of  geographical  distribution  vary  in 
different  classes,  and  even  in  different  families  and  species  of  the 
same  class.  Some  are  dispersed  over  regions  of  several  thousand 
miles  in  diameter,  while  others  of  the  same  genus  or  family  are 
restricted  to  a  few  square  miles. 

SECTION  VI.— DETERMINATION  OF  ORGANIC  REMAINS 

"Were  we  permitted  to  go  into  details,  it  might  easily  be  shown 
in  what  manner  important  inferences  may  be  drawn  from  very 

How  may  fresh-water  deposits  be  recognized?  How  estuary  deposits? 
What  other  information  may  be  derived  from  fossil  shells  ?  What  from  fossil 
plants?  How  are  terrestrial  animals  distributed  ?  What  is  said  of  the  differ 
ence  in  the  extent  of  distribution  of  different  species  ? 


DETERMINATION    OF    FOSSILS.  99 

imperfect  remains  of  animals  and  plants.  Often  only  a  tooth,  or 
a  few  scattered  fragments  of  bones,  or  even  the  tracks,  may  be 
all  the  relics  which  remain  to  testify  to  the  character  of  the  ex- 
tinct species.  The  determination  of  the  character  of  organic  re- 
mains, therefore,  becomes  a  problem  of  the  highest  importance, 
and  often  taxes  to  the  utmost  the  resources  of  science.  Nor  is  it 
a  question  of  scientific  interest  only ;  for,  since  the  real  character 
and  the  age  of  the  rock  is  to  be  determined  usually  by  the  nature 
of  the  organic  remains,  it  becomes  a  question  of  great  practical 
interest. 

Not  only  zoology  and  botany  contribute  from  their  boundless  re- 
sources to  the  aid  of  the  geologist,  but  comparative  and  vegetable 
anatomy  render  no  less  efficient  aid.  Every  tribe  of  animals  has 
some  peculiarities,  of  which  some  are  necessarily  connected,  and 
others  are  invariably  associated  without  any  obvious  connection. 

An  example  of  the  necessary  relations  between  parts  may  be 
seen  in  the  relation  of  the  claws  of  the  tiger,  or  of  any  kindred 
species,  to  the  other  parts  of  the  animal.  The  sharp,  curved,  re- 
tractile claws  are  fitted  for  seizing  and  tearing  its  prey,  and  all 
the  other  parts  appear  to  be  necessarily  associated  with  them. 
The  teeth  must  be  sharp,  and  adapted  for  cutting  flesh  rather  than 
for  bruising  grain ;  the  food  being  flesh,  the  digestive  apparatus 
must  be  less  complicated,  and  the  intestines  not  a  quarter  as  long 
as  in  herbivorous  animals ;  and  the  general  form  and  structure 
must  be  consistent  with  agility  in  order  to  seize  the  prey.  All 
these  and  many  more  details  would  be  inferred  from  finding  a 
single  retractile  claw,  whether  it  should  belong  to  any  known  or 
unknown  species,  and  with  the  aid  of  zoology  all  the  general 
characters  of  the  tribe  of  carnivorous  mammals,  with  their  anato- 
my and  physiology  in  their  numerous  details,  would  also  be  in- 
ferred. 

Of  the  characters  which  are  invariably  associated  without  ap- 

Why  are  imperfect  fossils  often  important  to  science  ?     Why  are  organic  re- 
mains of  economical  importance  ?     What  sciences  aid  in  determining  fossils  ! 
Describe  the  example  of  necessary  relations  of  parts.     What  is  said  of  associ- 
ted  characters  ? 


100       PRINCIPLES    OF    ZOOLOGY    WHICH    RELATE    TO    FOSSILS. 

parent  reason,  we  have  a  striking  example  in  the  ruminants,  for 
every  cloven-footed  quadruped  chews  the  cud,  and  thus  the  num- 
ber of  stomachs  is  infallibly  inferred  from  the  characters  of  the 
foot.  The  naturalist  is  familiar  with  numberless  examples  of  this 
curious  principle  in  zoology.  It  extends  even  to  color  and  cloth- 
<ng  as  well  as  to  form  and  structure,  so  that  certain  colors  only 
will  be  found  in  certain  species  or  groups  of  species. 

Both  of  these  principles  are  familiar  facts  in  reference  to  well- 
known  animals.  A  single  tooth  of  a  horse  will  show  not  only  to 
what  kind  of  animal  the  tooth  belonged,  but  even  his  age ;  and 
every  one  knows  that  a  green  horse,  a  blue  dog,  or  a  red  elephant 
are  as  unlikely  to  exist  as  a  ruminating  quadruped  with  four 
toes  or  with  the  solid  hoof.  Now  those  who  are  as  familiar  with 
the  various  tribes  of  organic  nature  as  the  husbandman  is  with 
his  cattle,  are  able  to  make  similar  inferences  respecting  the  mul- 
titude of  species  with  which  the  mass  of  mankind  are  unacquaint- 
ed. Thus,  when  a  single  tooth  of  the  iguanodon  was  shown  to 
Cuvier  before  the  discovery  of  the  skeleton,  he  laid  down  the 
characters  and  habits  of  that  herbivorous  reptile  with  an  accuracy 
which  the  subsequent  discoveries  have  only  confirmed.  A  single 
fish  scale  was  found  in  the  intestines  of  an  ichthyosaurus,  and 
shown  to  Professor  Agassiz,  who  recognized  it  as  belonging  to 
an  extinct  species  known  to  him,  and  he  was  able  to  point  out 
the  part  of  the  fish  to  which  it  was  originally  attached. 

In  the  vegetable  kingdom,  although  many  general  inferences 
may  be  made  from  parts,  yet  details  can  not  often  be  deduced  in 
this  way,  and  the  geologist  finds  fragments  of  plants  withe  ut  be 
ing  able  to  decide  whether  they  belonged  to  the  same  or  to  dif- 
ferent species. 

What  familiar  examples  are  mentioned  ?  What  is  said  of  Cuvier?  of  Agas 
HZ!  of  the  utility  of  fragments  of  fossil  plants? 


DURABILITY    OF    ORGANIC    BODIES.  101 


CHAPTER  II. 

FOSSILIZATION. 

THE  proportion  of  the  various  .tribes  o,f\ammala  which  are 
found  in  a  fossil  state  mast  depend  not  onlj  on  their  number,  but 
on  the  facility  with  which  they  may  oec preserved  •  J.t  becomes, 
therefore,  of  great  importance  to  consider  this  subject,  in  order  to 
avoid  erroneous  conclusions  respecting  the  Fauna  and  Flora  of 
former  epochs.  Thus  two  thirds  of  all  the  known  species  of  or- 
ganic remains  are  shells,  but  it  is  not  to  be  inferred  that  molluscs 
constituted  two  thirds  of  all  the  organic  beings  in  existence. 
The  durability  of  the  parts,  the  agents  of  burial,  and  the  nature 
and  process  of  petrifaction,  are  the  principal  topics. 

SECTION  I.— DURABILITY  OF  ORGANIC  BODIES. 

The  durability  of  parts  of  the  bodies  of  the  various  tribes  of 
animals  and  plants  differs  extremely,  and  is  found  to  correspond 
to  a  considerable  extent  with  the  relative  quantity  of  their  re- 
mains which  have  been  found  in  a  fossil  state.  It  is  therefore 
important  to  consider  this  subject  a  little  in  detail. 

I.  If  Vertebrated  animals  are  buried  so  deep  beneath  a  mass 
of  sand  or  mud  that  their  putrefying  bodies  can  not  rise  to  the 
surface,  their  skeletons  will  be  preserved  entire.  If,  however, 
they  are  not  thus  buried,  they  will,  soon  after  the  commencement 
of  putrefaction,  from  the  formation  of  gases,  become  lighter  than 
the  water,  and  float  on  the  surface ;  decomposition  will  be  more 
rapid,  and  the  bones  will  fall  scattered  to  the  bottom,  and  be 
gradually  covered  by  the  deposits  of  mud  or  sand  which  may  be 
going  on.  Birds,  however,  are  always  buoyed  up  by  their  f  sath- 
ers,  and  hence  only  scattered  bones  are  likely  to  be  preserved. 

What  is  said  of  the  proportions  of  various  tribes  of  fossil  remains  ?  What 
are  the  three  principal  topics  relating  to  fossilization  ?  What  is  said  of  th* 
durability  of  the  parts?  What  is  said  of  vertebrate d  animals?  of  birds? 


102  FOSSILIZATION. 

Their  bones  also  being  tubular,  are  more  likely  to  be  crushed 
than  those  of  other  veitebrata.  The  skeletons  of  some  fishes,  as 
the  sharks,  being  cartilaginous,  are  more  subject  to  decay,  but 
their  teeth,  being  very  hard,  are  preserved.  Accordingly,  the 
bones  of  birds  are  extremely  rare ;  and  while  the  skeletons  of 
many  kinds  of  fishes  are  common,  it  is  seldom  that  any  thing  more 
than  the  teeth  of  sharks  is  found.  Birds,  however,  frequently 
leave  their  t/acks  in  fine,  sand  and  mud  to  be  buried  by  additional 
layers  of  sediment,  and  although  little  search  has  been  made  by 
layirg  op-en 'strata  en  ths.  banks  of  rivers  and  on  the  shores  of 
the  sea,  a  number  of  examples  have  been  found.  It  will  be  seen 
in  the  sequel  that  the  tracks  of  birds  are  far  more  frequently  found 
in  the  rocks  than  are  any  other  relics  of  them. 

II.  Of  the  Articulata ;  insects,  although  far  more  numerous 
than  any  or  all  other  classes,  except  the  animalcules,  are  very 
rarely  preserved.  The  naturalist,  in  searching  for  objects  of  nat- 
ural history,  rarely  finds  dead  insects.  Multitudes  of  them,  with 
a  ferocious  activity,  prey  upon  each  other.  On  the  water  or  on 
the  land  they  are  the  favorite  food  of  numerous  tribes  of  veite- 
brata ;  bats,  lizards,  frogs,  fishes,  and  birds  devour  myriads. 
Permeated  by  the  innumerable  air  tubes  of  respiration,  they  after 
death  speedily  decay  by  atmospheric  agency.  Being  from  the 
same  cause  lighter  than  the  water,  they  are  rarely  buried,  but, 
like  birds,  float  on  the  surface,  without,  however,  eventually  drop- 
ping any  solid  parts,  but  either  decaying  or  becoming  the  prey 
of  fishes.  Rarely,  therefore,  either  in  the  recent  or  older  rocks, 
are  their  remains  found.  Yet  as  it  would  obviously  be  incorrect 
to  infer,  from  the  paucity  of  their  remains  in  alluvial  deposits, 
that  few  exist  at  the  present  day,  so  it  would  be  equally  erro- 
neous to  infer  positively  that  they  were  not  more  numerous  in 
former  periods  than  the  number  of  their  remains  would  indicate. 
The  remains  which  have  been  found  are  either  those  of  insects 
that  frequent  water,  and  are  therefore  more  likely  to  be  buried 

What  is  said  of  cartilaginous  fishes  ?  of  bird  tracks  ?  of  insects  ?  How  is 
the  scarcity  of  fossil  insects  accounted  for  ?  What  kinds  of  fossil  insects  are 
found? 


DURABILITY    OF   SHELLS.  103 

in  the  mud,  or  the  elytra  of  beetles,  which  are  the  most  inde- 
structible parts. 

Of  the  Myriapods  the  same  remark  may  be  made :  covered 
with  crustaceous  rings  of  about  the  consistence  of  the  harder 
parts  of  beetles,  they  are  about  equally  durable,  and  are  found 
about  as  frequently  in  their  haunts. 

Of  the  Arachnida  a  majority  are  extremely  frail,  but  a  few,  es- 
pecially the  scorpions,  are  as  durable  as  any  of  the  beetles,  being 
covered  with  a  hard  crust,  and  a  few  have  been  found  in  a  fossil 
state.  The  most  durable  species  of  this  class  are,  however,  not 
aquatic. 

Most  of  the  Crustaceans  are  covered  with  a  crust  much  harder 
than  any  of  the  preceding  articulata,  and  parts  of  some  of  them 
have  the  solidity  of  bones.  They  are  mostly  marine;  some,  es- 
pecially of  the  minute  species,  inhabit  fresh  water,  and  a  few  only 
are  capable  of  living  on  dry  land.  They  are,  therefore,  much 
more  frequently  preserved. 

Of  the  Cirrhopods,  many  are  covered  with  true  shells  of  solid 
carbonate  of  lime,  and  as  they  are  marine,  there  can  be  no  rea- 
son why  they  should  not  be  preserved  in  as  large  proportion  as 
any  tribes  of  organic  beings.  From  their  deficiency  in  the  geo- 
logical formations,  it  may  quite  safely  be  inferred  that  the  class 
is  of  comparatively  recent  introduction. 

Annelidans  are  less  durable  than  the  myriapods,  which  they 
resemble  in  their  general  form.  But  many  of  them  are  aquatic, 
and,  having  the  habit  of  burying  themselves  in  the  mud  or  sand, 
are  not  very  unlikely  to  be  preserved,  notwithstanding  the  ex- 
ceeding frailty  of  their  structure.  It  is  quite  remarkable  that 
some  of  the  oldest  animals  yet  described  as  existing  in  any  geo- 
logical formation  are  marine  worms  with  very  slender  and  per- 
ishable bodies.  Their  remains,  although  distinct,  usually  resem- 
ble faint  impressions.  The  tracks  of  earth-worms,  which  are  so 
abundantly  seen  immediately  after  a  heavy  rain  has  driven  them 
out  of  their  holes,  are  often  in  a  situation  to  be  soon  covered  with 

What  is  said  of  myriapods  ?  of  the  arachnida  ?  of  crustaceans  ?  of  cirrho- 
pods  ?  of  annelidans  ?  of  their  fossil  remains  ? 


104  FOSSILIZATION. 

a  layer  of  mud,  and  are  quite  likely  to  be  preserved.     Impres- 
sions on  some  of  the  solid  rocks  probably  have  a  similar  origin. 

III.  Of  the  Mollusca,  those  which  are  destitute  of  shells  are 
very  perishable.     Hence  their  remains  are  rare. 

But  a  great  majority  of  the  mollusca  are  furnished  with  durable 
calcareous  shells.  Of  the  several  classes,  the  shells  of  the  gastro- 
pods and  conchifers  are  most  solid  and  durable,  and  the  latter 
most  abound  in  species  whose  habit  is  to  live  buried  in  sand  or 
mud.  Yet  in  the  older  formations  they  are  either  very  rare  or 
entirely  wanting,  and  the  shells  of  the  cephalopods  and  brachio- 
pods  are  far  more  abundant,  although  at  the  present  time  they  are 
extremely  rare :  whence  it  may  be  safely  inferred  that  the  pro- 
portions of  these  great  classes  have  been  totally  reversed. 

Of  land-shells,  the  actual  number  of  living  species  is  probably 
nearly  as  great  as  «of  marine  species.  But  since  the  species,  fol 
the  most  part,  have  a  much  more  restricted  distribution,  they  are 
comparatively  less  known  to  naturalists.  The  same  cause  may 
be  an  obstacle  to  our  knowledge  of  extinct  species.  Terrestrial 
shells  are  also  much  less  likely  to  be  imbedded  and  preserved. 

IV.  Of  the  Nematoneura,  the  echinodermata  are  covered  with 
shells,  which  are  densely  crowded  with  calcareous  portions,  only 
less  solid  than  the  shells  of  molluscs  and  cirrhopods,  and,  from 
their  marine  habits  and  great  numbers,  they  are  likely  to  be  pre 
served.     Their  remains  are  common  in  many  of  the  formations. 

The  rotifera  and  bryozoa  are  not  uncommon  in  a  fossil  state, 
as  they  are  aquatic,  and  have  hard  parts  which  are  silicious  or 
calcareous.  Of  the  parasitic  classes  of  nematoneura,  it  would 
perhaps  be  premature  to  say  much  of  the  probability  of  their  ex- 
istence in  a  fossil  state ;  less  solid,  however,  than  most  of  the 
other  classes  of  this  division,  they  are  less  likely  to  have  been 
preserved,  jf  they  existed. 

V.  Acrita. — The  acalephae,  although  marine,  being  mere  gelat- 
inous masses,  with  but  a  few  grains  of  solid  matter,  are  very  un 

What  is  said  of  the  mollusca  which  have  no  shells  ?  What  shells  are  the 
most  durable  ?  What  are  most  abundant  in  a  fossil  state  ?  What  inference  1 
What  is  said  of  land-shells  ?  of  echinoderms  ?  of  the  acalephae  ? 


BURIAL    OF   ORGANIC   BODIES.  105 

likely  to  be  preserved.  The  absence  of  the  remains  of  these 
animals  from  geological  formations  affords,  therefore,  little  proof 
that  they  did  not  exist.  Of  the  polygastric  animalcules,  the  many 
which  had  shells  of  flint  leave  their  shells  in  extensive  deposits, 
as  before  remarked. 

Of  the  polypi  a  few  species  are  naked,  and  although  marine, 
their  soft  gelatinous  bodies  could  scarcely  be  preserved.  But 
the  great  number  of  coraliferous  species  are  engaged  in  the  in- 
voluntary labors  which  we  have  before  described,  and  their  du- 
rability is  proved  by  the  remains  of  corals  in  nearly  all  the  fossil- 
iferous  rocks. 

Sponges  have  sometimes  been  regarded  as  animal  and  some- 
times as  vegetable  bodies.  Their  situation  is  favorable  to  fossil- 
ization.  So  fine  is  their  texture  and  permeable  to  mineralizing 
agents,  that  the  microscopic  investigations  of  late  years  have  shown 
that  many  flint  nodules  in  chalk  consist  of  silicious  petrifactions  of 
sponges.  They  are  not  numerous  in  the  older  formations,  and,  had 
they  existed  abundantly  in  the  most  ancient  periods,  it  is  proba- 
ble that  their  remains  would  have  been  abundantly  preserved. 

SECTION  II.— BURIAL  OF  ORGANIC  BODIES. 

I.  Human  agency  has  exerted  a  powerful  effect  in  depositing 
in  the  earth  the  relics  of  man  himself,  both  human  skeletons  and 
objects  of  art. 

During  the  war  between  England  and  France,  in  the  earlier 
part  of  the  present  century,  125  British  ships  of  the  line  and  frig- 
ates, and  an  immense  number  of  smaller  vessels,  went  to  the  bot- 
tom. The  other  European  powers  suffered  a  much  greater  loss. 
During  the  year  1849,  there  were  566  British  vessels  wrecked. 
Probably  more  than  3000  European  and  American  vessels  are 
annually  lost.  Coins  in  immense  quantities,  seals  and  ornaments 
consisting  of  the  hardest  minerals,  and  often  engraved,  and  du- 
rable articles  of  glass,  earthenware,  &c.,  are  thus  buried  in  the 
marine  strata  which  are  now  in  the  process  of  formation. 

What  is  said  of  polypes  ?  of  sponges  ?  What  are  the  effects  of  human  agen 
tj  1  What  is  said  of  the  loss  of  vessels  ?  of  the  burial  of  works  of  art  in  ina 
rine  strata  ? 

E2 


106  FOSSILIZATION. 

Human  bones  are  as  durable  as  those  of  other  animals.  Cu- 
vier  says,  that  "  in  ancient  fields  of  battle  the  bones  of  men  have 
suffered  as  little  decomposition  as  those  of  horses  which  were 
ouried  in  the  same  grave."  They  have  been  found  in  a  fossil 
state,  and  even  in  solid  rocks.  The  most  remarkable  instance  is 
that  of  the  skeleton  found  in  a  fragmentary  rock  in  Guadaloupe. 
But  as  this  rock  is  daily  increasing  by  the  minute  fragments  of 
shells  and  corals  which  are  united  by  a  calcareous  cement,  no  re- 
mote antiquity  can  be  ascribed  to  these  remains.  In  short,  all  the 
remains  of  man  are  limited  to  deposits  which  are  of  recent  origin. 

II.  Natural  Agencies. — A  large  majority  of  the  organic  bodies 
which  are  imbedded  in  the  strata  now  forming  are  buried  by 
aqueous  agencies.  In  a  few  instances,  bodies  have  been  pre- 
served without  the  agency  of  water.  Thus  bodies  of  men,  and 
remains  of  birds  and  eggs,  have  been  found  in  guano ;  and  the 
moving  sands  of  deserts  bury  various  objects  which  may  be  pre- 
served indefinitely.  Animals  are  often  buried  in  caves  and  fis- 
sures by  inundations,  of  which  numerous  examples  have  been 
found  in  Europe.  Peatbogs  also  preserve  the  bodies  of  animals 
which  are  mired  in  them.  Peat  also  accumulates  over  and  pre- 
serves prostrate  forests.  The  only  vestiges  of  the  forests  described 
by  Julius  Caesar,  along  the  great  Roman  road  in  Britain,  are  the 
trunks  of  trees  in  peat.  In  frigid  climates,  animals  are  sometimes 
entombed  for  ages  in  ice. 

The  ejections  of  volcanoes,  as  we  have  seen,  may  bury  even 
entire  cities,  and  various  organic  bodies  may  be  preserved  in  the 
same  manner. 

Floods  and  storms  often  bury  immense  numbers  of  organic 
beings.  In  1787,  on  the  coast  of  Coromandel,  there. was  a  flood 
occasioned  by  a  hurricane  which  drove  the  waters  of  the  sea  in- 
land 20  miles.  This  flood  covered  the  country  with  mud,  in 
which  were  the  bodies  of  10,000  inhabitants  and  100,000  domes- 
tic animals.  When,  however,  animals  are  buried  permanently 

What  is  said  of  the  durability  of  human  bones  ?  What  is  the  character  of 
most  natural  agencies  1  Give  examples  of  agencies  not  aquatic.  What  is  said 
of  floods  and  storms  on  sea-coasts  ? 


PETRIFACTION.  107 

beneath  the  water,  the  probability  of  their  preservation  is  much 
greater  Such  may  have  been  the  effect  of  the  earthquake  wave 
which  in  1780  rushed  over  the  city  Savanna  la  Mar,  in  Jamaica, 
and  swept  away  the  whole  town,  leaving  not  a  vestige  of  man, 
beast,  or  habitation  on  the  surface. 

But  the  most  efficient  agents  are  the  floods  of  rivers,  by  which 
plants  and  animals  are  borne  into  deep  water  and  often  into  the 
sea,  and  permanently  submerged.  In  these  cases  the  bodies  may 
be  buried  at  once  beneath  a  heavy  mass  of  sand  and  stones. 
Even  marine  animals  are  often  destroyed  by  the  mass  of  mate- 
rials swept  down  in  floods. 

"  We  are  informed  by  Humboldt  that,  during  the  periodical 
swellings  of  the  large  rivers  in  South  America,  great  numbers  of 
quadrupeds  are  annually  drowned.  Of  the  wild  horses,  for  ex- 
ample, which  graze  in  immense  troops  in  the  savannah,  thou- 
sands are  said  to  perish  when  the  River  Apure  is  swollen,  before 
they  have  time  to  reach  the  rising  ground  of  the  llanos.  The 
mares,  during  the  season  of  high  water,  may  be  seen,  with  their 
colts,  swimming  about  and  feeding  on  grass,  of  which  the  top 
alone  waves  above  the  waters."  *  *  *  "  In  Scotland,  in  August, 
1829,  a  fertile  district  on  the  east  coast  became  a  scene  of  dread- 
ful desolation,  and  a  vast  number  of  animals  and  plants  were 
washed  from  the  land,  and  found  scattered  around  the  mouths  of 
the  principal  rivers.  An  eye-witness  thus  describes  the  scene 
which  presented  itself  at  the  mouth  of  the  Spey,  in  Morayshire  : 
For  several  miles  along  the  beach,  crowds  were  employed  in 
endeavoring  to  save  the  wood  and  other  wreck  with  which  the 
heavy  rolling  tide  was  loaded ;  while  the  margin  of  the  sea  was 
strewed  with  the  carcasses  of  domestic  animals,  and  with  millions 
of  dead  hares  and  rabbits.'  " — Lyell. 

The  solid  parts  of  marine  animals,  as  bones  of  fishes,  and  the 
shells  of  molluscs,  of  Crustacea,  and  of  echinodermata,  are  of 
course  often,  at  the  death  of  the  animal,  in  places  favorable  for 

What  is  said  of  the  floods  of  rivers  ?  What  example  in  South  America  ? 
Describe  the  example  in  Scotland.  What  is  said  of  the  situation  of  the  solid 
parts  of  fishes  and  other  marine  animals  ? 


108  FOSSIL1ZAT10N. 

preservation,  or  are  swept  into  such  places.  Thus,  to  the  east 
of  the  Faroe  Islands,  a  bed  of  sand  and  mud,  full  of  broken  and 
entire  shells,  has  been  traced  for  twenty  miles  ;  and  for  the  space 
of  three  and  a  half  miles  in  length,  the  mud  is  so  full  of  fish  bones, 
that  the  sounding  lead  is  seldom  drawn  up  without  some  verte- 
brae attached.  Between  Gibraltar  and  Ceuta,  fragments  of  shells 
have  been  found  on  a  gravelly  bottom  at  the  depth  of  4800  feet, 
carried  thither  by  a  current.  Fishes  are  also  buried  by  sub- 
marine eruptions  of  lava  or  mud. 

Most  of  the  genera  of  mollusca  have  aquatic  habits,  and  exist 
in  great  numbers  in  places  favorable  for  their  preservation.  Not 
a  few  live  buried  in  mud  or  sand,  where  after  death  only  the  soft 
parts  perish.  The  proportion,  therefore,  of  those  which  are  pre- 
served should  by  far  exceed  that  of  any  other  division  of  the  ani- 
mal kingdom.  We  are,  therefore,  not  surprised  that  fossil  shells 
should  constitute  the  greater  portion  of  many  strata  of  the  fossil- 
iferous  rocks  of  all  ages. 

SECTION  III.— MODES  AND  DEGREES  OF  PRESERVATION. 

I.  "Petrifaction  consists  in  the  substitution  of  particles  of  min 
eral  matter  in  the  place  of  the  particles  of  vegetable  or  animal 
matter,  and  consequently  preserves  the  structure  of  the  original 
body.     In  some  cases  this  process  is  known  to  take  place  at  the 
present  time,  as  when  bones  are  enveloped  in  clay  containing  sul- 
phuret  of  iron.     Sticks,  nuts,  &c.,  in  a  place  where  bog  iron  ore 
is  accumulating,  are  found  to  have  been  converted  into  ore,  prob- 
ably within  a  few  years.     Leaves  have  been  artificially  baked  in 
clay,  and  then  resembled  ancient  petrifactions.     But  little,  how- 
ever, is  known  of  the  process  of  petrifaction,  for  the  chemical  con- 
ditions favorable  to  it  are  more  likely  to  exist  under  a  pressure 
of  superincumbent  materials  excluded  from  the  air. 

II.  In  some  cases  the  space  occupied  by  the  organic  body  is 
left  empty,  and  only  a  mold  remains.     When  this  is  filled  with 
mineral  matter,  we  have  a  cast  of  the  body,  which  differs  from  a 

What  is  said  of  the  habits  of  most  mollusca  ?  What  is  petrifaction  1  What 
modern  examples  of  petrifaction  are  mentioned?  What  are  molds  1  casts? 


COMPARISON    OF   FOSSIL    Am    LIVING    SPECIES.  109 

petrifaction  in  the  absence  of  an  organic  structure.  The  interior 
of  shells  is  usually  filled  with  sand  or  mud,  and  when  the  shell 
subsequently  decays  without  petrifaction,  a  cast  of  the  interior 
only  remains.  Frequently  we  find  casts  of  the  shells  themselves 
containing  the  casts  of  their  interior. 

III.  The  calcareous  shells  of  molluscs  and  of  echinoderms,  and 
the  bones  of  vertebrated  animals,  are  often  preserved  through  sev- 
eral geological  periods  without  other  change  than  the  loss  of  the 
animal  matter.     Multitudes  are  found  in  this  condition  in  the  ter- 
tiary and  cretaceous  formations.     It  is  obviously  inaccurate  to  call 
such  fossils  petrifactions. 

In  Siberia  a  mammoth  and  a  rhinoceros  have  been  preserved 
since  the  pleistocene  period  in  ice,  with  their  flesh  entire.  Hu 
man  bodies  have  been  preserved  in  peat  bogs  for  more  than  a 
thousand  years. 

IV.  Various  bodies  are  incrusted  with  depositions  of  carbon- 
ate of  lime  from  calcareous  springs,  and  are  often,  but  very  erro- 
neously, called  petrifactions.    They  are  not  fossils  unless  they  be- 
long  to  a  remote  period. 

SECTION  IV.-COMPARISON  OF  THE  NUMBER  OF  FOSSIL  AND  LIVING 
SPECIES. 

It  may  be  interesting  to  show,  in  a  tabu  ar  form,  the  compar 
ative  number  of  species  known  to  be  living,  and  of  those  which 
have  been  found  in  a  fossil  state. 

Classes  or  divisions.  Living  species.  Extinct  species. 

Mammalia 1,500 275 

Birds 8,000 20 

Reptiles 1,500 120 

Fishes 8,000 1,500 

Insects 100,000 250 

Articulata 3,000? 500 

(Other  than  insects.) 

Molluscs 20,000 6,000 

Polypi 1,000? 900 

Echinodermata 200 700 

Animalcules 800 100 

Plants .100,000 ...1,800 

244,000  12,165 

What  examples  are  mentioned  of  preservation  without  petrifaction  ?  Whal 
is  said  of  incrustations  ?  What  is  the  number  of  known  species  of  existing  an- 
imals and  plants  1  of  extinct  species  ? 


110  FOSSILIZATION. 

In  this  comparison,  the  first  column  comprises  the  species  of 
one  period,  and  the  second  those  of  hundreds  of  periods.  The 
comparative  deficiency  in  the  number  of  extinct  species  is  due  to 
three  causes  :  first,  the  liability  of  many  tribes  to  perish  without 
being  fossilized;  second,  the  small  portion  of  the  fossil  remains 
which  appear  on  the  surface,  the  great  majority  being  concealed 
within  the  strata,  while  the  living  species  are  on  the  surface,  and 
exposed  to  notice  also,  in  the  case  of  many  animals,  by  their  habits 
of  activity ;  third,  the  greater  number  of  observers  and  collectors 
of  the  existing  species  of  animals  and  plants.  Of  so  much  conse- 
quence are  these  three  principal  circumstances,  that,  with  some 
exceptions,  it  would  be  mere  speculation  to  make  a  definite  com- 
parison of  the  actual  numbers  of  living  and  of  extinct  species. 

Why  are  so  few  extinct  species  known  7 


PART   III. 


HISTORY  OF  THE  EARTH. 

THE  first  and  second  parts  of  our  subject  may  be  regarded  as 
preliminary  to  the  third,  in  which  we  come  directly  to  the  history 
of  the  earth.  In  this  history  the  geologist  describes  the  condi- 
tion of  the  earth  in  successive  periods,  in  respect  of  the  distribu- 
tion of  land  and  water,  the  features  of  the  land,  the  climate,  the 
sedimentary  deposits  and  igneous  rocks,  and  the  successive  gen- 
erations of  animals  and  of  plants. 


CHAPTER  I. 
SOURCES  OF  KNOWLEDGE. 

THE  direct  sources  of  knowledge  are  to  be  found  in  the  rocks, 
which  have  been  formed  during  the  successive  periods  of  the  past. 

SECTION  I.— RELATIVE  AGE  OF  THE  STRATIFIED  ROCKS. 

The  basis  of  the  whole  history  is  a  knowledge  of  the  relative 
age  of  the  rocks. 

I,  This  is  ascertained  primarily  from  the  position  of  the  strata 
of  the  sedimentary  rocks.  It  is  obvious  that  the  vertical  order  in 
a  series  of  the  strata  is  the  order  of  time ;  that  the  lowest  stratum 
was  first  deposited,  and  that  the  uppermost  one  is  the  most  re- 
cent. In  this  way  we  learn  the  relative  age  of  those  stratified 
rocks  which  are  found  in  junction. 

What  does  Geology  describe  in  the  history  of  the  earth  ?  What  is  the  basis 
of  the  history  ?  What  may  be  learned  from  the  order  of  the  strata  ? 


112  SOURCES    OF    KNOWLEDGE. 

II.  But  all  the  strata  do  not  occur  in  any  one  place  in  junction, 
and  their  relative  age  is  usually  ascertained  in  the  following  man- 
ner :  If  the  actual  chronological  order  be  represented  by  the 
order  of  the  letters  of  the  alphabet,  we  may  have  in  one  place 
the  series  A,  B,  C,  E,  G- ;  in  another,  C,  D,  E,  F,  G ;  in  another, 
A,  B,  M,  N,  P,  &c.  Thus  the  parts  of  a  complete  series  occur 
in  different  places.  These  parts  may  be  arranged  with  ease  and 
accuracy  in  the  order  of  time,  provided  that  we  are  able  to  iden- 
tify synchronous  strata ;  or,  to  recur  to  our  illustration,  when  the 
formations  A,  B,  C,  E,  G-  occur  in  one  place,  and  C,  D,  E,  F,  G 
in  another,  we  must  be  able  to  identify  C  and  E  in  the  second 
series  with  C  and  E  in  the  first  series.  This  is  done  by  thejfas- 
sils.  Each  formation  is  characterized  by  peculiar  fossils ;  and, 
having  become  acquainted  with  the  species  in  the  formations  in 
each  local  series,  we  find  that  those  of  C  and  E  are  the  same  in 
both  series.  We  then  infer  the  synchronism  of  these  formations. 
But  since  the  species  of  animals  and  plants  differ  widely  on 
distant  parts  of  the  earth's  surface,  we  can  not  expect  thus  to  de 
termine  an  exact  synchronism  between  the  formations  of  very 
distant  countries.  This  difficulty  is  found  to  be  less  in  the  older 
formations  than  would  have  been  anticipated,  because  it  appears 
that  there  was,  during  their  deposition,  a  much  greater  uniform- 
ity in  the  animal  and  vegetable  kingdom  than  at  the  present  time. 
The  differences  also  between  the  Faunae  and  Florae  of  periods, 
which  are  in  geological  time  quite  remote  from  each  other,  are 
greater  than  between  those  of  a  given  period,  which  are  geograph- 
ically distant. 

III.  Another  means  of  directly  proving  the  relative  age  of 
rocks  occurs  when  we  find  the  fragments  of  one  stratified  rock 
in  another.     The  inference  is  then  unavoidable,  that  the  first  was 
not  only  deposited,  but  consolidated  before  the  latter  was  formed. 

IV.  The  synchronism  of  deposits  in  distant  regions  may  also 

Is  the  series  of  strata  complete  in  any  one  place  ?  How  is  the  fact  illus- 
trated ?  How  can  distinct  formations  of  the  same  age  be  identified  ?  What 
difficulty  is  mentioned?  What  is  the  third  method  of  ascertaining  the  relative 
age  of  rocks  ?  the  fourth  method  ? 


SYNCHRONISM    OF    STRATA.  113 

be  approximately  established,  in  the  case  of  the  later  geological 
periods,  by  a  comparison  of  their  fossils  with  existing  species.  In 
receding  from  the  present  time,  the  proportion  of  extinct  species 
will  be  found  to  increase,  until  we  arrive  at  a  period  anterior  to 
the  existence  of  any  of  the  present  races.  If  the  introduction  of 
new  species  and  the  extinction  of  old  ones  had  taken  place  with 
a  uniform  rate  in  all  times  and  places,  we  should  have  a  means 
of  measuring  time  with  a  degree  of  precision  proportioned  to  the 
completeness  of  the  collections  of  fossils.  Although  the  rate  of 
change  may  not  have  been  characterized  by  exact  uniformity, 
this  principle  is  of  the  highest  utility  in  geological  investigations. 
This  method  may  be  illustrated  by  taking  A,  B,  C  for  a  series  of 
successive  deposits  in  one  region,  and  a,  b,  c  for  a  similar  series 
in  another  place.  If  all  the  fossils  in  A  and  a  belong  to  existing 
species,  we  may  refer  the  deposits  to  the  present  period.  If  in 
B  and  b  ten  per  cent,  belong  to  extinct  species,  they  are  syn- 
chronous, and  are  referred  to  a  previous  period ;  if  in  C  and  c 
thirty  per  cent,  are  extinct,  they  are  synchronous,  and  more  an 
cient  than  B  and  b. 

The  same  method  may  be  extended  to  a  comparison  of  any 
formations  which  immediately  succeed  each  other  in  position. 
If  many  of  the  fossils  are  common  to  both,  we  may  infer  that  they 
are  not  remote  in  geological  time.  The  converse,  however,  evi- 
dently may  not  be  true  when  two  successive  deposits  contain  the 
remains  of  animals  of  very  different  habits,  as  marine  species  in 
one  and  fresh  water  species  in  another. 

V.  More  or  less  aid  is  sometimes  derived  from  the  lithologicaJ 
characters  of  the  strata.  The  lithological  characters  comprise 
the  mineral  constitution  and  the  structure.  They  depend  partly 
on  original  deposition  and  partly  on  subsequent  changes.  Their 
peculiarities  are  dependent  much  more  on  local  circumstances 
than  on  the  period  of  time  during  which  the  deposit  was  formed. 
Thus,  during  the  same  period,  chalk  beds  were  formed  in  En- 
gland and  strata  of  sand  in  New  Jersey.  The  lithological  char« 

How  is  this  method  illustrated  ?  How  may  it  be  applied  to  ancient  fop 
Inai  ions  ?  What  is  said  of  the  lithological  characters  ? 


114  HISTORY    OF    THE    PERIODS. 

acters  are  used,  in  determining  the  age  of  rocks,  with  much  cau- 
tion and  to  a  limited  extent. 

VI.  The  minerals  which  are  disseminated  through,  or  associa- 
ted with  certain  strata,  may  also  be  of  some  service  in  ascertain- 
ing their  age.  Some  minerals  appear  to  have  been  formed  more 
abundantly  during  certain  periods. 

SECTION  II.— RELATIVE  AGE  OF  THE  UNSTRATIFIED  ROCKS. 

The  age  of  unstratified  rocks  may  often  be  more  or  less  accu- 
rately determined  by  their  association  with  stratified  rocks.  It 
is  obvious  that  an  igneous  rock  must  be  more  recent  than  the 
strata  through  which  it  has  been  erupted.  It  is  not  always  cor- 
rect to  infer  that  strata  which  lie  over  an  igneous  rock  are  there- 
fore more  recent,  since  the  igneous  rocks  may  have  failed  to  pen- 
etrate all  the  overlying  strata.  Frequently,  however,  it  can  be 
determined  by  local  circumstances  whether  the  overlying  strata 
were  there  at  the  time  of  eruption. 

SECTION  III.— HISTORY  OF  EACH  PERIOD 

After  having  fixed  the  relative  chronology  of  the  formations, 
we  may  learn  from  their  organic  remains  the  characters  and  hab- 
its of  the  plants  and  animals  of  each  period.  From  these  data 
we  infer  the  peculiarities  of  climate,  and  from  the  same  data  and 
the  lithological  characters  of  the  strata  we  may  learn  much  re- 
specting the  distribution  of  land  and  water,  and  the  features  and 
extent  of  the  land.  From  the  strata  themselves,  and  from  the 
unstratified  rocks  associated  with  them,  we  learn  much  respecting 
the  aqueous  and  igneous  agencies  of  the  period. 

Since,  also,  some  thick  deposits  thin  out  in  certain  directions, 
it  may  be  inferred  that  the  materials  of  which  they  are  composed 
were  derived  from  the  opposite  direction ;  in  other  words,  that 
there  was  an  island  or  continent  in  that  direction,  the  size  of 
which  and  of  its  rivers  must  have  been  in  some  measure  propor- 
tionate to  that  of  the  formation  derived  from  it. 

What  is  said  of  the  mineral  contents  of  the  strata  ?  How  is  the  age  of  the 
unstratified  rocks  ascertained?  What  may  be  learned  from  the  organic  re« 
mains  of  the  strata  ?  What  from  differencss  of  thickness  ? 


MEANS    OF   OBSERVATION.  115 

From  the  alternation,  in  some  cases,  of  fresh  water  with  ma- 
rine formations,  it  is  also  obvious  that  some  portions  of  the  earth 
have  been  subject  to  both  elevation  and  subsidence  repeatedly. 

It  appears  to  have  been  the  general  fact  that  the  palaeozoic  for- 
mations, with  their  fossils,  were  uniformly  spread  over  much  more 
extensive  areas  than  the  secondary  and  tertiary  formations ;  the 
change  from  the  former  to  the  latter  is  not,  however,  abrupt,  but 
the  deposits,  for  the  most  part,  are  more  limited,  as  they  are  more 
recent. 

With  the  exception  of  some  metamorphic  districts,  and  some 
very  limited  fresh-water  formations,  the  greater  part  of  existing 
continents  is  covered  with  strata  which  abound  with  marine  fos- 
sils. These  fossils,  with  scarcely  any  exceptions,  are  the  remains 
of  animals  and  plants  which  lived  and  died  in  the  places  where 
they  are  now  found.  This  is  attested  by  the  preservation,  in  nu- 
merous instances,  of  parts  so  delicate  that  they  would  have  been 
destroyed  by  transport,  and  also  by  the  nature  of  the  stratum  in 
which  they  are  found,  which  corresponds  to  the  known  station  of 
kindred  species  now  living. 

It  is  obvious,  therefore,  that  the  existing  continents  have  been 
under  the  ocean  since  the  commencement  of  the  palaeozoic  pe- 
riod. 


CHAPTER  II. 

MEANS   OF  OBSERVATION. 

THE  means  by  which  the  rocks  are  exposed  to  observation  are 
both  artificial  and  natural. 

SECTION  I.— ARTIFICIAL  EXCAVATIONS. 

Excavations  for  roads  and  canals  often  expose  the  rocks  and 
the  superficial  deposits  to  a  considerable  depth.  Fresh  excava- 

What  may  be  learned  from  the  alternation  of  marine  and  fresh-water  strata  ? 
What  is  said  of  the  extent  of  the  older  formations  ?  What  proof  that  the 
existing  continents  have  been  under  the  ocean  since  the  palaeozoic  periods  ? 
What  is  said  of  artificial  excavations  ? 


116 


INCLINATION    OF    THE    STRATA. 


dons  are  especially  useful  in  exhibiting  the  order  and  structure 
of  the  unconsolidated  strata.  Artesian  wells  (p.  72)  often  furnish 
valuable  information  respecting  the  order  of  the  strata,  as  well  as 
concerning  the  internal  temperature. 

Mines  are  yet  more  useful  to  geologists.  The  deepest  is  that 
of  the  Eselschacht  in  Bohemia,  which  is  3778  feet  deep.  The 
greatest  depth  below  the  sea-level  is  that  of  some  coal  mines  in 
Newcastle,  England,  which  are  from  1500  to  2000  feet  below 
this  level.  Since  many  deep  mines  are  carried  to  a  great  hori- 
zontal extent  in  following  metallic  veins  or  beds  of  coal,  they 
have  furnished  a  great  amount  of  knowledge  on  those  subjects. 

SECTION  II.— NATURAL  MEANS. 

I.  Excavations  by  Water. — Among  the  natural  means  are  the 
excavations  by  rivers.     The  section  of  the  rocks  which  is  exhib- 
ited in  the  channel  of  the  Niagara  is  seven  miles  long,  and  from 
150  to  300  feet  deep.     The  structure  of  an  uneven  country  is 
often  best  exhibited  by  the  river- courses  and  the  lines  of  sea-coast. 

II.  Uplifts. — Yet  more  instructive  are  those  uplifts  where  the 
strata  on  one  side  of  a  fracture  have  been  lifted  up,  forming  a 
precipice.     The  order  of  several  successive  formations  is  often 
thus  exhibited,  and  the  geologist  is  able  with  great  facility  to  as- 
certain, also,  their  characters,  contents,  and  thickness. 

A  beautiful  example  of  this  kind  is  found  in  Snake  Mountain, 
in  the  valley  of  Lake  Champlain.  Here  most  of  the  lower  part 
of  the  Silurian  system  is  shown  within  the  distance  of  less  than 
half  a  mile,  as  in  the  following  figure  : 

Fig.  31. 


SECTION   OF    SNAKE    MOUNTAIN,  ADDISON    COUNTY,  VT. 

c.  Fracture. 

What  is  said  of  mines  ?  of  excavations  by  water  ?  of  uplifts  ?     Describe  th« 
example. 


MEANS  OP   OBSERVATION.  117 

t'.  Brown  clay,  extending  six  miles  west  to  Lake  Champlain, 
where  it  covers  (n)  the  Trenton  and  Isle  la  Motte  limestones. 
b.  Calciferous  sandrock  ;  dip*  10°. 

d.  Isle  la  Motte  limestone,  dip  increasing  from  10°  to  20°. 
a.  Trenton  limestone ;  dip  25°. 
g.  Utica  slate ;  dip  38°. 

h.  Hudson  River  shales ;  mostly  covered  with  drift  and  debns. 
k.  Debris,  from 
I.  Red  sandrock ;  dip  20°. 
«.  Cranberry  meadow,  over  liquid  peat. 

This  example  has  been  espe  ially  useful  in  deciding  in  the  neg* 
ative  an  important  question  which  had  arisen  in  American  Geol- 
ogy, as  to  the  existence  of  a  Taconic  System  older  than  the  Si 
lurian  System. 

III.  Inclination  of  the  Strata. — But  the  limits  of  geological  ob- 
servation would  be  very  narrow  if  it  were  restricted  ordinarily 
to  a  thickness  of  a  few  hundred  feet,  with  some  rare  opportuni- 
ties in  high  mountains  and  deep  mines.  By  means  of  the  incli- 
nation of  the  strata,  we  become  acquainted  with  the  structure  of 
the  earth  to  the  depth  of  many  miles.  The  convulsions  of  an- 
cient times  have  more  or  less  broken  and  lifted  up  the  layers  of 
the  stratified  rocks,  so  that  few  of  them  now  lie  in  their  original 
position.  The  layers  must  once  have  been  nearly  or  quite  hori- 
zontal. If  Lake  Erie  should  be  drained,  extensive  layers  of  sed- 
iment would  appear,  and  if  these  should  be  consolidated,  frac- 
tured, and  inclined  by  igneous  agency,  their  whole  structure  and 
contents  would  be  exhibited. 

Most  of  the  older  strata  have  been  repeatedly  subjected  to  ig- 
neous agencies,  while  various  aqueous  agencies  have  more  or  less 
modified  the  parts  which  have  been  thus  exposed.  But  the  nat- 
ural and  artificial  sections  of  canals,  rail-roads,  rivers,  and  sea- 
coasts  more  or  less  perfectly  exhibit  the  upturned  edges  of  the 
ancient  strata.  It  is  obvious  that  when  we  pass  over  the  surface 

*  Dip  is  the  inclination  below  the  horizon. 

What  can  we  learn  from  the  inclination  of  the  strata  ?  What  must  have 
been  their  original  position?  How  are  their  edges  exhibited?  What  ctn 
we  learn  by  traveling  across  their  edges  ? 


118  CLASSIFICATION    OF    THE    SFEATIFIED    ROCKS. 

of  the  ground  directly  across  the  edges  of  the  layers,  we  obtain 
the  same  knowledge  of  their  order,  structure,  and  contents  which 
we  should  have  obtained  by  a  perpendicular  descent  had  the 
strata  retained  their  original  horizontal  position.  If,  for  exam- 
ple, we  travel  six  miles  across  the  edges  of  strata,  which  have  a 
dip  of  45°,  their  thickness  will  be  found,  by  a  trigonometrical  cal- 
culation, to  be  a  little  more  than  four  miles.  It  is  quite  unnec- 
essary, therefore,  for  the  geologist  to  descend  into  the  earth  to 
learn  the  structure  of  its  crust.  Probably  all  the  formations,  and 
consequently  all  the  materials  for  a  chronological  history  of  the 
earth,  have  been  exposed  to  the  light  of  the  sun. 


CHAPTER  III. 

CLASSIFICATION  OF  THE  STRATIFIED  ROOKS. 
SECTION  I.— CLASSES  OF  STRATA. 

I.  THERE  are  five  classes  of  stratified  rocks.     The  first  and  old- 
est are  called  primary  strata,  and  are  characterized  by  their  po- 
sition beneath  the  fossiliferous  rocks.     Many  of  the  strata  which 
were  once  referred  to  this  class  of  rocks  have  been  proved  to 
have  been  originally  fossiliferous  and  are  now  mctamorphic  ;  that 
is,  the  fossils  have  been  obliterated,  and  their  structure  has  been 
rendered  crystalline  by  heat.     Such  rocks  belong  mostly  to  the 
next  two  classes.     Probably  very  few  of  the  supposed  primary 
strata  will  eventually  remain  in  this  class. 

II.  The  second  class  includes  those  strata  which  contain  the 
remains  of  the  earliest  organic  beings,  and  a  long  series  of  subse- 
quent formations.     They  are  called  Palceozoic  rocks  (from  two 
Greek  words,  which  signify  ancient  animals),  because  they  con- 
tain the  remains  of  the  earliest  animals  known  to  have  existed. 
Most  of  them  have  also  been  called  Transition  rocks,  because 

What  are  the  primary  strata?     What  are  metamorphic  rocks?     What  is 
said  of  the  palaeozoic  rocks? 


CLASSES    OF    STRATA.  119 

they  were  once  supposed  to  have  been  formed  during  a  transi- 
tion of  the  earth's  surface  from  an  uninhabitable  to  a  habitable 
state. 

III.  The  third  class  contains  another  long  series  of  formations, 
commencing  with  the  New  Red  Sandstone,  in  which  occur  the 
extraordinary  bird  tracks  discovered  and  described  by  President 
Hitchcock,  and  terminating  with  the  chalk  formation.    They  have 
been  called  Secondary  Rocks,  and  also  Mesozoic  Rticks — the  word 
mesozoic  signifying  animals  of  the  middle  periods. 

All  the  animals  of  the  palaeozoic  and  mesozoic  periods  have 
long  since  become  extinct. 

IV.  The  fourth  class,  called  the  Tertiary  or  Camozoic  strata, 
consists  of  regular  and  nearly  horizontal  strata  of  limestone,  sand, 
and  clay ;  and,  with  many  extinct  species  of  anLnals  and  plants, 
they  contain  some  which  still  exist.     The  word  cainozoic  signi- 
fies new  or  recent  animals. 

V.  The  fifth  class,  called  the  Quaternary  strata,  comprises  the 
unstratified  masses  of  sand,  gravel,  pebbles,  &c.,  termed  drift,  and 
all  the  subsequent  deposits  up  to  the  present  time. 

What  is  said  of  the  mesozoic  rocks?  of  ti«  tertiary  strata  f  of  the  qua  tor 
nary  strata? 


120 


CLASSIFICATION    OF    THE    STRATIFIED    ROCK. 


SECTION  II.— TABULAR  VIEW  OF  THE  FORMATIONS. 

The  following  table  exhibits  the  classes,  orders,  systems,  di- 
visions, and  formations  of  all  the  stratified  rocks,  the  average 
thickness  of  the  formations,  and  the  countries  where  they  are 
most  freely  developed. 


I 


S3rstems.    Divisions. 


1 

f 

Alluvium. 

Varia- 
ble. 

1 

Newer  Pleistocene. 
Older  Pleistocene. 

200 

Southern  States, 
Verm't.,  Canada. 

1 

{Tr^     •_ 

Northern  States, 

<y 

bT 

•British  Am.,  and 

^6  }           } 

J  JNorth'n  Europe. 

111 

Pleiocene. 

2,0001  England,  Italy, 

•^    *2     v                  V. 

Meiocene. 

500  >France,Southern 

gj|    1 

Eocene. 

1,000]      States. 

'^.S 

„       f               fMaestricht  beds. 

f™ 

~s  S 

g  d  1  Chalk.  <!  Chalk  with  flints. 

1,000    *" 

Newer  Se 
"  Mesos 

§  S 

S  <^ 

fS  «  < 
0  >~> 

S  QQ 

0 

![  Chalk  without  flints. 
P      >     f  Upper  Green  Sand. 

n  '  [  Lower  Green  Sand. 

^  New  Jersey, 
,       48()    England, 
M  Western  Europa 

r  Weald  Clay. 

Wealden.        \  Basting's  Sand. 

900 

[Purbeck  Strata. 

j 

£.8 

TT          f  Portland  Stone. 
JPP6;    Portland  Sand. 
Uollte'  [Kimmeridge  Clay. 
Upper  Calcareous  Grit.; 

•      500 

*. 

H. 

S 

Middle 
Oolite.  ' 

Coral  Rag. 
Lower  Calcareous  Grit.  I       450 
Oxford  Clay. 

s 

rS  S 

op. 

Kelloway's  Rock. 

England. 

8 

§! 

o 

rCornbrash. 
Forest  Marble. 

MH 

| 

Great  Oolite. 

Lower 

Carbonaceous  and 

•       450 

Oolite.  ' 

Stonesfield  Slate. 

Inferior  Oolite. 

Calcareo-silicious  Sand.. 

,/  . 

o  d           r  uPPer  Lias- 

E*.S 

\  Marlstone.                        1 

•"d  S 

J  S                 1  Lower  Lias  Shale.         f      70° 

1  1 

i-5  oo                  [  Lower  Lias  Limestone.  J 

dgss 

4o  g                  r  Variegated  Marls  or      1 

Germany, 

11 

tKeuper.                       1 
1  Muschelkalk.                 f      90° 

Massachusetts, 
and  Connecticut 

O  °  I  £""  <»                1  Bunter  Sandstone.         | 

CLASSES    OF    STRATA. 


121 


»      Systems.        Divisions.                          Formations. 

J5           »- 
O        O 

Thickness.                Countmi. 

.1  c  C  Magnesian     Zechstein. 

500] 

|  !|  I  Limestone.     Bituminous  and 

[England. 

*<»                           Argillaceous  Schist. 

300  [Germany. 

0 

- 

Lower  New  Red. 

'o 

N 

S 

New  Shales. 

1  New  Brunswick. 

i 

1 

New  Coal  Measures. 

5700 

Virginia,  Ohio, 

'rt   i    oo" 

Serai 

Older  Shales. 

,/  uu 

Michigan,  Penn- 

1 

CO 

Series. 

Older  Coal  Measures.   . 

sylvania,  En- 

£4 
0) 

o 

3, 

Silicious  Conglomer- 
ate. 

|   1,400 

gland,  Illinois, 
Kentucky. 

Carboni 

Shales  and  Sandstone.  " 
r  Carboniferous  Lime- 
stone. 
.  Lower  Red  Shale 

1  Western  States. 
>  3,000  \  Virginia, 
Pennsylvania. 

Vespertine 
Series.     ' 

(Yellow  Quartzose 

u 

s  s 

Upper     )      Sandstone. 

£< 

o 

!| 

""3  .2  ' 

Division. 

1  Impure  Limestone. 
Gritty  Red  Sandstone. 
(Gray  Fossil  Sand- 
>     stone. 

•  10,000 

Russia, 
Scotland, 
•  Pennsylvania. 
Ohio, 

Middle 
Division. 

C 

{variegated  Sandstone. 
Bituminous  Schists. 

Michigan. 

i 

O  Q 

Coarse  Sandstones. 

Great  Conglomerate. 

Chemung  Group. 

1,500 

g 

g 

Portage  Group. 

1,000 

N 

"C 

Erie 

Genesee  Slate. 

150 

§  * 

{§ 

Division. 

Tully  Limestone. 

16 

« 

OQ 

Hamilton  Group. 

1,000 

1 

Marcellus  Slate. 

50 

CM 

f  Uormterous  Limestone. 

70 

P 

Onondaga  Limestone. 

14 

Schoharie  Grit. 

d 

a 

1 

Helderberg 
Series. 

Cauda  Galli  Grit. 
Oriskany  Sandstone. 
Upper  Pentamerus 
Limestone. 

70 
700 

Western  States, 
•New  York, 
Great  Britain. 

2 

Encrinal  Limestone. 

J 

OQ 

-a  - 

Delthyris  Shaly  Limestone.  1  00 
Pentamerus  Limestone.          80 

i' 

o 

Water  Lime  Group. 
Onondaga  Salt  Group. 

100 
700 

o 

o 

(Niagara  Group. 
Ontario     1  Clinton  Group. 

164 
80 

Division.    j  Medina  Sandstone. 

350 

I  Oneida  Conglomerate. 

500. 

Ked  bandrock. 

400 

a 

Hudson  River  Group. 

600 

*C 

Utica  Slate. 

100 

I 

Champlain  ,  Trenton  Limestone. 
Division.  1  1sle  la  Motte  Marble. 

400 
25 

Vermont, 
'New  York. 

fe 

Bird's-eye  Limestone. 

30 

o 

Calciferous  Sandrock. 

300. 

* 

(Potsdam  Sandstone. 

3  (TO    New  York. 

Primary  strata- 


122  CLASSIFICATION    OF    THE    STRATIFIED    ROCKS. 

"We  proceed  now  with  a  hasty  sketch  of  the  geological  history 
of  the  earth.  It  would  seem  more  natural  in  a  historical  science 
to  commence  with  the  most  remote  period  of  antiquity,  and  to  fol- 
low down  the  course  of  time.  But  the  condition  oi  the  earth  in 
its  earliest  ages  was  so  unlike  the  present,  in  its  geography,  its 
climate,  and  all  its  features,  that  there  is  little  in  common  between 
the  most  ancient  and  the  present  period,  except  that  the  same  rr.3.- 
terial  atoms  and  the  same  laws  of  nature  remain.  He  who  for 
the  first  time  becomes  acquainted  with  this  extraordinary  history, 
is  lost  in  the  strange  scenes  of  those  earliest  days,  unless,  proceed 
ing  step  by  step  from  the  present  to  tne  past,  he  shall  have  be- 
come gradually  accustomed  to  the  change. 

"We  shall  therefore  trace  up  the  stream  of  time  into  the  remote 
legions  of  the  past.  Each  system  will  be  the  subject  of  a  distinct 
chapter,  commencing  with  the  most  recent. 

A  strictly  chronological  order  would  require  that  all  the  events 
of  the  geological  history  should  be  narrated  in  the  precise  order 
of  their  occurrence ;  that  the  characters  derived  by  the  strata 
from  agencies  acting  on  them  subsequently  to  their  deposition 
should  be  described  as  belonging  to  the  time  when  those  agen- 
cies acted.  So  much,  however,  remains  to  be  discovered,  in  order 
to  render  geology  complete  in  this  respect,  that  it  is  impossible 
to  observe  strictly  a  chronological  order.  We  shall  therefore  de- 
scribe the  phenomena  of  the  strata  in  the  reversed  order  of  their 
original  deposition.  The  time  is  probably  distant  when  geolo- 
gists will  narrate  events,  as  well  as  classify  deposits,  in  a  strictly 
chronological  order. 

What  order  of  time  will  be  followed  in  this  work  ?  What  order  would  bs 
desirable? 


DRIFT.  V2B 


CHAPTER  IV. 
QUATERNARY   SYSTEM. 

THE  dependence  of  the  formations  of  this  system,  each  on  the 
preceding,  is  both  so  obvious  and  so  intimate,  that  we  shall  com- 
mence with  the  first  in  the  order  of  time,  when  the  features  of  the 
earth  were  quite  similar  to  those  of  the  present  day. 

SECTION  I.— DRIFT. 

The  name  of  this  deposit,  Drift,  is  derived  from  the  fact  that 
all  its  materials  have  evidently  been  drifted  in  a  common  or  sim- 
ilar movement.  All  its  phenomena  either  are  consistent  with  or 
directly  prove  this  fact.  The  most  important  facts  may  be  refer- 
red to  the  following  heads  : 

L  Lithological  characters. 

2.  The  geographical  limits  of  the  drift. 

3.  The  transport  of  the  materials. 

4.  The  wearing  down  of  the  solid  rocks. 

5.  Streams  of  stones. 

6.  The  absence  of  fossils  from  unaltered  drift. 

7.  The  crushing  of  slate  hills. 

I.  LitJwlogical  Characters. — The  deposits  of  this  period  con- 
sist of  sand,  gravel,  hard-pan,  pebbles,  and  bowlders  variously 
mingled,  and  sometimes  have  a  very  irregular  and  confused  strat- 
ification. 

The  pebbles  and  bowlders,  especially  the  latter,  are  distinctly 
scratched.  But  a  large  portion  of  the  materials  which  were 
originally  accumulated  during  this  period  has  been  remodeled, 
without  much  change  of  place,  during  a  subsequent  period.  The 
original  unaltered  drift  is  recognized  by  the  striae  on  the  peb- 
bles, and  by  a  more  dense  structure.  It  is  rarely,  if  ever,  found 

Why  is  the  drift  so  called?  What  are  the  principal  classes  of  facts  relating 
to  it?  What  arc  its  lithological  characters  ? 


124  QUATERNARY    SYSTEM. 

in  North  America  on  the  surface  at  less  than  4CO  feet  above  the 
present  sea  level. 

II.  The  Geographical  Limits  of  Drift. — The  deposits  of  this 
period  cover  this  continent  north  of  40°  north  latitude,  and  in 
the  valleys  of  the  Delaware,  Susquehanna,  and  Mississippi  they 
extend  a  few  degrees  further  to  the  south. 

In  Europe  they  occupy  the  northwestern  part,  reaching  to  the 
ocean  on  the  north  ;  commencing  a  little  east  of  the  White  Sea, 
their  boundary  extends  in  a  southeasterly  direction  nearly  to  the 
Ural  Mountains,  in  latitude  61°,  then  southwesterly  through  the 
central  region  of  Russia  nearly  to  latitude  51°,  and  thence  west- 
erly in  a  very  irregular  zigzag  line  through  the  southern  parts  of 
Poland  and  Prussia.  The  great  irregularities  of  the  southern 
boundary  are  due,  as  in  the  United  States,  to  southerly  elonga- 
tion in  valleys. 

Drift  is  also  said  to  occur  in  high  latitudes  in  the  southern 
hemisphere,  as  in  Patagonia  and  in  the  Falkland  Islands.  It  is 
wanting  within  the  tropics.  The  few  accounts  which  have  been 
given  of  its  existence  in  the  West  Indies  are  based  on  the  de- 
posits of  rivers  which  formerly  flowed  at  higher  levels  and  were 
subjected  to  violent  freshets. 

III.  Transport  of  Drift. — 1.  In  the  regions  of  unaltered  drift, 
the  greater  accumulations  appear  to  have  been  on  mountains. 
On  the  lower  parts  of  the  Green  Mountains  of  Vermont,  at  an  el- 
evation of  1000  to  2000  feet,  drift  so  uniformly  and  abundantly 
covers  the  surface,  that  the  solid  rocks  are  wholly  concealed 
throughout  extensive  distripts.     The  extreme  height  of  drift  in 
North  America  is  about  5000  feet  above  the  sea  level.     The 
summit  of  Mount  Washington  is  the  only  part  of  New  England 
which  was  above  its  reach.     Within  its  geographical  limits  and 
below  a  certain  height,  the  drift  appears  to  have  been  distribu 
ted  without  much  regard  to  levels,  and  is  universal.     In  this  re 
spect  it  differs  from  all  aqueous  deposits. 

What  are  the  limits  of  drift  on  this  continent?  what  in  Europe?  What  is 
said  of  drift  in  southern  latitudes?  in  the  West  Indies?  >Vhat  is  said  of  the 
accumulations  of  drift  ? 


TRANSPORT    OF   DRIFT.  1^5 

2.  The  direction  of  the  transport  is  ascertained  by  tracing  the 
materials  of  the  drift  to  the  source  from  which  they  were  derived, 
In  almost  every  place  there  are  local  peculiarities  of  the  rocks 
which  the  practiced  eye  of  the  geologist  easily  recognizes,  so  that 
the  fragments  which  have  been  removed  may  be  identified  with 
their  original  source.     In  North  America,  the  direction  of  trans- 
port was  generally  to  the  south  or  a  little  east  of  south,  rarely 
varying  on  account  of  local  causes  from  ten  degrees  west  of  south 
to  a  little  south  of  east. 

In  Europe  the  phenomena  are  quite  different.  The  materials 
have  been  dispersed,  in  nearly  straight  lines,  from  the  mountains 
of  Scandinavia  as  a  center. 

3.  The  distance  of  transport  differs  much  in  different  places, 
and  especially  in  respect  of  different  parts  of  the  materials.     The 
great  mass  of  the  materials  is  derived  from  ledges  which  occur 
within  a  few  miles.     It  is  rarely  the  fact  that  the  greater  portion 
of  the  gravel  or  pebbles,  or  even  jf  the  bowlders,  have  traveled 
more  than  five  or  ten  miles.     If  in  some  places  the  bowlders 
which  have  come  from  a  greater  distance  are  more  numerous 
than  those  of  the  neighboring  rocks,  it  is  because  the  latter  are 
more  perishable.     Such  cases  are  therefore  no  real  exception  to 
the  general  statement. 

The  distance  to  which  isolated  bowlders  have  been  transported 
is  sometimes  very  great. 

In  Vermont,  heavy  iron  ore  has  been  earned  30  or  40  miles. 
On  Long  Island,  Nantucket,  and  Martha's  Vineyard,  bowlders 
are  found  which  were  derived  from  the  continent.  It  is  thought 
that  some  bowlders  in  New  England  have  been  removed  100 
miles.  In  Ohio  and  other  Western  States,  bowlders  are  found 
which  were  derived  from  the  rocks  north  of  the  Great  Lakes, 
and  which  must  have  been  transported  several  hundred  miles. 

4.  In  general,  there  is  a  very  close  correspondence  between  the 
durability  of  the  rocks  and  the  abundance  of  bowlders  and  peb- 
bles derived  from  them  and  contained  in  the  drift.     Durability 

What  is  said  of  the  manner  of  ascertaining  the  direction  ?  of  the  direction  in 
North  America?  in  Europe  ?  of  the  distance?  of  the  durability  and  abund- 
ance of  bowlders  ? 


126  QUATERNARY    SYSTEM. 

depends  on  the  power  of  resisting  either  chemical  or  mechanical 
agencies.  Very  soft  slate  rocks  are  unaffected  by  the  solvent 
powers  of  lain,  but  are  often  impressible  by  the  finger  nail.  Yet 
such  rocks  are  found  to  retain  now  the  finest  striae,  which  were 
imprinted  on  them  by  the  mechanical  agency  of  the  drift  period, 
But  their  fragments  enter  very  sparingly  into  the  composition  of 
the  drift.  Limestone  is  not  only  soft,  but  decays  also  by  solution. 
It  is  therefore  deficient  in  the  drift  even  of  limestone  regions. 

On  the  other  hand,  a  narrow  strip  of  quartz  rock,  on  the  west- 
ern flank  of  the  Green  Mountains,  has  filled  the  drift  with  peb- 
bles and  bowlders,  whose  ellipsoidal  form  has  procured  the  pro- 
vincial appellation  of  "  hard-heads." 

It  is  scarcely  necessary  to  remark  that  the  detachment  of  the 
fragments  and  the  rounding  of  their  angles  are  not  to  be  exclu- 
sively ascribed  to  the  drift  agency.  The  ordinary  agencies  of 
rivers  and  waves,  and  of  the  atmosphere,  are  ever  producing 
these  results.  If,  as  there  is  good  reason  to  believe,  extensive 
regions,  which  are  covered  with  drift,  were  above  the  ocean  dur- 
ing many  long  periods  anterior  to  the  drift,  these  agencies  were 
probably  producing  bowlders,  pebbles,  and  other  loose  materials. 
Then  came  the  drift  agency,  adding  more  or  less  to  these  mate- 
rials, but  operating  eminently  as  an  agent  of  dispersion.  Since 
the  lapse  of  time  would  alike  accumulate  the  durable  and  con- 
sume the  more  perishable  fragments,  we  find  here  one  cause  of 
the  deficiency  of  the  latter,  in  comparison  with  the  extent  of  the 
parent  rocks.  The  long-continued  violence  of  the  drift  agency 
itself  was,  however,  an  additional  cause  of  this  deficiency. 

5.  Hills  and  mountains,  not  exceeding  1000  or  2000  feet  in 
height,  do  not  appear  to  have  presented  any  insurmountable  ob- 
stacles to  the  passage  of  the  materials.  G-ravel  and  bowlders  are 
often  more  abundantly  accumulated  on  the  north  sides  of  mount- 
ains. But  examples  are  very  common  of  large  bowlders  having 
been  carried  up  steep  acclivities  to  great  heights. 

How  were  many  of  the  bowlders  originally  rounded  ?  What  are  the  two 
causes  of  greater  abundance  of  more  durable  bowlders  ?  What  is  said  of  the 
obstacles  presented  to  the  drift  by  mountains? 


STRIATED    ROCKS.  127 

On  Hoosac  Mountain,  in  the  town  of  Adams,  Massachusetts,  is 
a  bowlder  weighing  six  hundred  or  seven  hundred  tons,  which 
has  been  transported  across  a  valley,  and  one  thousand  feet  up 
the  mountain.  On  the  summits  of  Mount  Holyoke  range  are 
large  fragments  of  sandstone,  which  have  been  carried  up  an 
almost  perpendicular  precipice  several  hundred  feet  from  the  val- 
ley beneath. 

6.  The  size  of  some  of  the  transported  bowlders  is  enormous. 
One  in  Fall  River,  Massachusetts,  weighs  5400  tons.  The  ped- 
estal for  the  statue  of  Peter  the  Great  was  hewn  from  a  bowlder 
which  weighed  1500  tons. 

IV.  The  Wearing  down  of  Solid  Rocks. — 1.  The  transport  of  the 
drift  over  the  solid  rocks  acted  more  or  less  to  wear  them  down, 
producing  well-rounded  and  smoothed  surfaces,  on  which  are 
stricB  and  furrows.  There  being  no  exception  to  the  general 
fact  of  coincidence  between  the  direction  of  the  stria?  arid  that 
of  the  movement  of  the  drift  materials,  the  one  may  be  taken  as 
an  index  of  the  other.  But  from  the  great  facility  and  precision 
with  which  the  direction  of  these  striae  may  be  measured,  they 
afford  the  best  means  of  ascertaining  the  direction  of  the  drift 
movement. 

In  some  cases,  on  the  tops  of  mountains  of  the  tougher  rocks, 
as  on  Mount  Holyoke,  in  Massachusetts,  furrows  are  found  which 
are  a  foot  wide  and  two  inches  deep.  In  Dorchester,  Massa- 
chusetts, the  sides  of  an  angle  between  two  portions  of  a  ledge 
of  hard  quartzose  conglomerate,  which  were  nearly  in  the  direc- 
tion of  the  drift,  were  rendered  concave  and  smooth,  as  if  the 
moving  bodies  were  forced  through  with  great  friction. 

More  frequently  the  furrows  are  but  an  inch  to  three  inches  in 
width  and  about  a  third  as  deep.  Still  more  frequently  scratches 
occur  which  do  not  exceed  one  eighth  or  one  fourth  of  an  inch  in 
width,  and  others  are  as  fine  as  the  stroke  of  a  pen. 

Sometimes  the  entire  surface  of  the  rock  is  smoothed  down, 
rounded,  and  polished,  as  in  the  case  of  the  Dorchester  rocks 
above  mentioned,  where  the  surface  of  the  hard  quartz  pebbles 

What  is  said  of  the  size  of  bowlders  1  of  the  direction  of  the  stria?  and  fuf 
rows  ?  of  the  size  of  the  furrows  and  striae  ?  of  polished  surfaces  ? 


128 


aUATERATARY   SYSTEM. 


is  a  little  in  relief,  like  the  silicious  specks  in  a  piece  of  marble 
artificially  polished. 

Perhaps  no  part  of  North  America  has  furnished,  within  an 
equal  space,  so  many  beautiful  examples  of  polished  and  striated 
rocks  as  have  been  found  in  Vermont.  In  that  state  more  than 
three  hundred  examples  (reckoning  as  distinct  cases  those  only 
which  are  at  least  one  quarter  of  a  mile  distant)  have  been  found. 

Among  the  districts  most  remarkable  for  their  abundance  is 
the  valley  of  the  Winooski.  There  the  perfectly  rounded  sur- 
faces of  the  talcose  slate,  the  broad  furrows,  and  delicate  scratch- 
es were  protected  by  a  fluviatile  deposit  of  fine  sand,  during  the 
long  subsequent  period  of  the  older  pleistocene,  and  therefore 
have  a  freshness  which  adds  much  to  the  beauty  and  interest  of 
these  results  of  the  drift  agency.  In  the  northwest  part  of  this 
state  few  ledges  of  rocks  can  be  found  which  are  not  rounded 
and  furrowed.  In  this  region,  many  furrows  are  from  12  to  20 
inches  wide,  and  3  or  4  inches  deep.  The  recent  removal  of  clay 
often  exposes  a  striated  surface  of  marble,  which  retains  a  polish 
nearly  equal  to  that  of  artificially  polished  marble. 

The  limestone  of  Addison  county  abounds  with  well-smoothed 
surfaces  covered  with  scratches,  which  have  been  protected  from 
decay  by  a  covering  of  brown  clay,  and  have  within  a  few  years 
been  exposed  in  the  gulleys  at  the  road  side.  Fig.  32  represents 
the  drift  stria3  in  black  marble,  near  Lake  Champlain,  in  Shore* 
nam,  Vt. 

•pig  32  a    is    the    abrupt    com- 

mencement     of      several 
coarse  stria?. 

b  b  is  a  furrow  which 
appears  to  have  been  the 
effect  of  unequal  pressure, 
perhaps  the  rolling  of  a 
loose  pebble. 

c  c  is  a  broad  furrow  in 
the  bottom  of  which  pieces 
were  broken  out,  probably 

DRIFT  FURROWS   AND  STRIDE,  SHOREHAM,  VT.      *,  &  7 

gular  stone. 
Furrows  and  striae  are  wanting  on  surfaces  of  limestone  which 


What  is  said  of  examples  in  Vermont  ?     Describe  the  specimen  represented 
n  Fig.  32.     What  is  said  of  limestone  surfaces  ? 


STRIATED    ROCKS. 


129 


have  been  long  exposed  to  atmospheric  agencies.  The  surfaces 
of  rocks  which  are  more  or  less  feldspathic,  as  the  granite  and 
gneiss  regions,  and  which  decay  by  yielding  up  their  potassa, 
have  rarely  retained  the  furrows.  The  same  is  true  of  surfaces 
which  crumble  by  the  admission  of  water  into  a  porous  or  loose- 
ly laminated  structure.  The  parallelism  of  the  stria3  is  one  of 
their  most  obvious  characters.  On  very  convex,  and  even  on 
hemispherical  surfaces,  there  is  scarcely  any  perceptible  devia- 
tion from  parallelism.  Glacial  furrows  and  striee  differ  from 
those  which  are  made  by  fluviatile  agency.  The  former  are 
straight,  or  sometimes  slightly  and  regularly  curved ;  the  latter 
are  very  irregular  and  tortuous.  Both  kinds  of  furrows  are  rep- 
resented in  the  accompanying  figure. 

Fig.  33. 


CASCADE    OF    H6NNE    VOSS,   NORWAY. 

a  a.  Furrows  made  by  the  river,     b  b.  Glacial  striae,     c  c. 
Glacial  furrows. 

Some  furrows  and  impressed  lines  on  the  surfaces  of  rocks  re- 
semble drift  striae  and  furrows,  but  are  due  to  structure.     They 

What  is  said  of  the  parallelism  of  striae  ?  of  the  difference  between  fluvia- 
tile  and  glacial  furrows  ?     What  is  said  of  furrows  owing  to  structure  ? 

F  2 


130  QUATERNARY    SYSTEM. 

are  produced  by  the  unequal  weathering  of  the  strata,  and  maybe 
very  easily  distinguished  from  those  which  have  resulted  from  an 
external  mechanical  force.  Furrows  are  also  produced  by  the 
solvent  power  of  rain  on  limestone  slopes,  but  they  are  too  irreg- 
ular to  resemble  drift  furrows. 

2.  Furrows  and  striae  are  wanting  only  where  the  rock  is  un- 
dergoing disintegration.  It  would  not,  therefore,  be  an  unreason- 
able inference,  that  the  entire  surface  of  the  rocky  floor  of  the 
northern  parts  of  this  continent  was  smoothed  into  cavities  and 
convexities,  and  covered  with  furrows  and  scratches  by  the  drift 
agency. 

.3.  The  greatest  elevation  at  which  drift  furrows  exist  is  an 
interesting  question  which  has  received  some  attention.  They 
exist  abundantly  on  Jay  Peak,  at  the  northern  extremity  of  the 
Green  Mountain  range.  The  height  of  this  summit  is  4025  feet 
above  the  ocean.  From  the  size  of  the  furrows,  we  can  hardly 
avoid  the  conclusion  that  such  agency  was  nearly  or  quite  as  en- 
ergetic as  at  lower  levels. 

On  the  White  Mountains  of  New  Hampshire  are  drift  furrows 
at  an  elevation  of  5000  feet  above  the  sea.  This  is  the  greatest 
height  at  which  they  have  been  found  in  North  America.  Above 
6000  feet,  the  summit  of  Mount  Washington  entirely  escaped  the 
effects  of  the  drift  agency. 

On  the  other  hand,  the  lowest  level  reached  by  the  striae  is  un- 
known. They  are  seen  descending  beneath  the  sea,  where  it  is 
impossible  to  trace  them  any  further. 

4.  The  minor  inequalities  of  surface,  such  as  hills  and  isolated 
rocks,  did  not  perceptibly  influence  the  direction  of  the  current. 
But  the  general  direction  was  essentially  modified  by  the  promi- 
nent features  and  outlines  of  the  surface.  In  Vermont,  the  Green 
Mountain  range  has  a  direction  nearly  north  and  south,  and  is 

What  is  said  of  furrows  caused  by  rain  ?  of  the  universality  of  the  polishing 
und  striating  agency?  of  the  height  at  which  furrows  exist  on  the  Green 
Mountains  1  on  the  White  Mountains  ?  of  their  lowest  level  ?  What  is  said  of 
the  influence  of  the  minor  inequalities  of  surface  ?  of  mountain  ranges  and 
valleys  ? 


STOSS    AND   LEE    SIDES.  131 

crossed  by  the  valley  of  the  Winooski.  On  either  side  of  the 
valley  the  mountains  rise  to  a  height  of  3000  and  4000  feet. 
Here  the  current  was  deflected  so  as  to  ascend  the  valley  in  near- 
ly an  easterly  direction.  The  same  is  true  of  the  valley  of  the 
Lamoille,  a  few  miles  further  north.  But  on  the  tops  of  the  ad- 
jacent mountains  the  current  held  its  usual  north  and  south  di- 
rection. But  the  proximity  of  longitudinal  valleys  appears  to 
have  deflected  the  current  at  greater  elevations.  Thus,  in  Put- 
ney, Vermont,  striae  on  the  west  side  of  a  mountain  have  a  di- 
rection to  the  southwest. 

5.  The  north  and  west  sides  of  the  ledges  of  rocks,  having  been 
most  exposed  to  the  drift  agency,  are  often  very  perfectly  round- 
ed, forming  the  roclies  moutounees  of  European  writers ;  but  the 
opposite  sides  have  generally  escaped  the  influence  of  this  agen- 
cy. To  the  former  or  struck  side  has  been  applied  the  epithet 
stoss  (Swedish  for  struck),  and  the  latter  is  called  the  lee  side. 

An  interesting  example  is  found  on  the  south  side  of  the  Wi- 
nooski, in  Bolton,  Vermont.     In  this  example  there  is  a  peculi- 
arity, that  the  rock  is  shelving  on  the  stoss  side,  as  below  a  in 
Fig.  34.  Fig.  34.     a  e  is  the  stoss  surface 

covered  'with  furrows  and  striae, 
and  c  e  is  the  lee  side,  a  m  and 
c  e  are  entirely  destitute  of  any 
marks  of  drift  agency.  It  is  very 
obvious  that  the  surface  ara  proves 
that  the  drift  agency  was  that  of 
a  solid.  Any  bodies  moving  in  a 
liquid,  like  bowlders  and  pebbles 
in  water,  would  have  exerted  their 
greatest  force  against  this  shelv- 
ing surface. 

The  same  phenomena  appear  on  a  larger  scale  in  the  stoss 
and  lee  sides  of  mountains.  The  effects,  however,  were  modified 
by  the  original  form  and  structure  of  the  mountains.  Thus  the 
lee  sides  of  many  of  the  Green  Mountains  are  on  the  east,  al- 
though the  direction  of  the  drift  agency  was  but  little  east  of 
south.  Those  mountains  which  are  most  isolated  on  the  north 
and  west  sides  were  most  modified  in  their  outlines.  Thus  Cam- 

What  is  said  of  the  north  and  west  side  of  rocks  t  Describe  the  example 
represented  in  Fig.  34.  What  is  said  of  the  stoss  and  lee  sides  of  mountains  1 


132  QUATERNARY    SYSTEM. 

el's  Hump,  in  Vermont,  owes  its  present  form  almost  entirely  tt 
the  drift  agency,  the  steep  and  irregular  lee  side  being  on  the 
south,  and  the  well-rounded  outline  on  the  north,  for  this  mount- 
ain, rising  up  suddenly  on  the  south  side  of  the  Winooski,  un- 
protected by  any  considerable  elevation  to  the  north  or  west, 
received  the  full  force  of  the  drift  agency. 

6.  In  numerous  examples  of  striated  rocks,  two  or  more  dis- 
tinct sets  of  striae  may  be  recognized  with  different  directions,  but 
those  of  each  set  are  parallel.     At  Hill's  quarry,  on  the  Isle  la 
Motte,  in  Lake  Champlain,  there  are  eight  sets  ;*  but  it  is  not 
usual  to  find  more  than  two  or  three  sets  at  one  locality.     It  is 
probable,  nowever,  that  the  earlier  striae  of  other  directions  were 
entirely  obliterated  by  the  long  continuance  of  the  drift  agency. 

It  is  often  possible  to  determine  the  relative  age  of  the  striae. 
But  much  discrimination  is  requisite,  for  one  which  is  shallow 
may  appear  to  have  been  cut  off  by  another  which  is  narrow  and 
deep,  and  yet  the  latter  may  or  may  not  be  the  older  ;  or,  if  the 
striae  are  of  nearly  equal  depth,  it  may  not  be  possible  to  arrive 
at  any  conclusion.  But  when  a  small  one  is  continued  across  the 
bottom  of  a  somewhat  deeper  and  much  broader  stria,  and  when 
several  such  examples  occur  on  the  same  surface,  there  can  be 
no  doubt  of  their  relative  age.  We  have  succeeded  in  determ- 
ining the  relative  age  of  two  sets  of  striae,  in  about  thirty  exam- 
ples in  Vermont,  and  find  no  exceptions  to  the  general  conclu- 
sion that  those  which  had  the  more  westerly  origin  are  the  more 
recent.f 

7.  In  the  northwestern  countries  of  Europe  the  drift  radiates 
from  the  Scandinavian  Mountains.     In  other  respects,  as  to  the 
character  of  the  striae  and  furrows,  the  rounded  and  polished 

*  These  directions  are,  south  8°  west,  south  3°  west,  south  10°  east,  south 
25°  east,  south  43°  east,  south  45°  east,  south  47°  east,  and  south  65°  east.  In 
Vermont,  those  striae  which  have  a  direction  of  south  10°  east  are  most  abund- 
ant; next  are  those  which  run  south  20°  to  30°  east. 

t  In  one  case,  that  of  Hill's  quarry  above  mentioned,  the  age  of  three  seta 
was  determined  as  follows,  beginning  with  the  oldest,  south  10°  east,  south 
8°  west,  and  south  47°  east. 

What  is  said  of  different  sets  of  striae  ?  of  the  relative  age  of  such  striae  ?  of 
the  striae  and  polished  rocks  in  Scandinavia  ? 


STREAMS    OF    STONES.  133 

rocks,  and  the  stoss  and  lee  sides  of  rocks  and  mountains,  the 
drift  phenomena  in  Norway  and  Sweden  are  similar  to  those  in 
North  America.  The  greatest  height  at  which  striae  occur  in 
Scandinavia  is  nearly  6000  feet.  They  descend  beneath  the  sea 
to  unknown  depths.  In  other  parts  of  the  northwestern  half  of 
Europe  they  are  less  common. 

8.  That  the  striae  and  furrows  belong  to  the  same  period  with 
the  drift,  being  indeed  the  effect  of  the  transport  of  the  latter, 
has  been  regarded  as  sufficiently  proved  by  the  coincidence  of 
direction,  and  by  the  want  of  any  deposits  intervening  between 
the  striated  rocks  and  overlying  drift.  It  necessarily  follows  that 
they  are  as  ancient  as  the  drift  accumulations.  It  can  also  be 
shown  that  they  immediately  preceded  the  deposition  of  the  ple- 
istocene, which  is  more  recent  than  the  drift ;  for,  wherever  a 
surface  has  been  recently  uncovered,  the  most  delicate  striae  aro 
found  to  have  been  preserved  by  a  few  inches  of  clay.  It  follows, 
then,  that  the  furrows  and  striae  could  not  have  been  long  exposed 
to  atmospheric  agencies  which  would  have  obliterated  them.  It 
would  not,  of  course,  follow  that  the  striating  agency  was  limit- 
ed to  this  point  of  time,  which  indicates  its  close  only.  It  had 
undoubtedly  been  continued  through  a  long  series  of  ages. 

V.  Streams  of  Stones. — 1.  The  type  of  this  class  of  phenomena 
was  discovered  in  Richmond,  Massachusetts,  by  President  Hitch- 
cock, and  has  since  elicited  much  attention.  These  streams  arc 
arranged  in  long  lines,  and  consist  of  an  enormous  quantity  of 
angular  fragments  of  rock,  overlying  the  common  drift,  and  ex- 
tending from  a  ledge  of  the  same  kind  of  rock  in  the  direction 
of  the  drift  current. 

From  their  position  it  is  inferred  that  they  were  formed  at  or 
near  the  close  of  the  drift  period.  It  is  not,  however,  to  be  sup- 
posed that  this  effect  was  peculiar  to  the  end  of  the  period,  for 
whatever  similar  streams  may  have  been  strewed  along  previous- 
ly would  subsequently  have  been  either  rearranged  or  buried 


What  is  said  of  their  greatest  height?  What  proves  the  striae  to  be  as  an- 
cient aa  the  drift?  What  proof  that  they  immediately  preceded  the  pleisto- 
cene ?  What  are  streams  of  stones  ?  What  is  said  of  their  age  1 


[34 


QUATERNARY    SYSTEM. 


beneath  other  drift.  A  considerable  portion  of  erratic  blocks 
may  have  been  distributed  in  the  same  manner  ;  but  well-char- 
acterized examples  are  rare,  and  difficult  of  recognition. 

2.  A  very  interesting  example  occurs  in  Huntington,  Vermont. 

Fig.  35  Fig.  35  represents  the  prominent  local  feat- 

ures. 

A  hill,  a  7i,  rises  150  feet  above  the  valley, 
m  n.  It  consists  of  fine  talcose  slate,  and  is 
about  one  fourth  of  a  mile  long,  with  a  width 
of  sixty  to  eighty  rods. 

On  the  west  is  a  small  hill  of  the  same  kind 
of  talcose  slate,  g.  The  west  side,  b  c  d  k,  of 


the  principal  hill  is  very  precipitous.  A  long 
narrow  ledge  of  very  coarse  binary  syenite,  sy, 
lies  in  the  talcose  slate,  on  the  south  side. 

Furrows  and  scratches  on  the  slate,  ffy  have 
a  direction  south  15°  east. 

The  stream  of  angular  stones  is  prolonged 
nearly  a  mile  beyond  the  southern  termination 
of  the  hill  toward  i  k,  in  the  direction  of  the 
drift  current.  The  stones  were  evidently  derived  from  the  ledge, 
*  y,  for  they  consist  wholly  of  the  same  peculiar  variety  of  sy- 
enite. 

The  most  characteristic  example  of  streams  of  stones  occurs  in 
the  western  part  of  Massachusetts,  and  is  represented  in  Fig.  36. 
There  are  two  distinct  streams,  which  have  their  sources,  A  C, 
between  Canaan  and  Lebanon,  in  New  York,  at  the  summit  of 
the  Taconic  range  of  mountains. 

The  train  A  B  has  been  traced  20  miles,  and  the  other,  C, 
about  10  miles  to  the  southeast.  This  is  the  direction  of  the 
drift  striae  in  the  vicinity.  They  are  300  to  400  feet  wide,  are 
nearly  parallel,  and  are  from  one  half  to  one  third  of  a  mile  apart. 
It  will  be  seen  in  the  figure  that  they  pursue  a  southeast  course 
obliquely  across  mountains  and  valleys,  with  little  or  no  regard 
to  these  inequalities  of  surface.  The  two  ranges  of  mountains 
which  they  cross  are  each  about  100  feet  higher  than  the  source 
of  the  stones,  and  are  about  800  feet  higher  than  the  first  valley 
which  they  cross. 

The  stones  in  these  trains  consist  of  a  peculiar  metamorphic 


Why  are  distinct  examples  rare  ? 
the  one  in  Masaaclj  usetts. 


Describe  the  example  in  Vermont,  and 


AGE    OF    DRIFT. 


135 


feldspathic  rock,  of  a  greenish 
color,  which  is  very  easily  dis- 
tinguished from  the  slates  and 
limestones  over  which  they  lie. 
It  is  found  in  ledges  only  along 
!  the  crest  of  the  Taconic  ridge. 
The  very  spot  whence  the  stones 
were  derived  is  conspicuous 
The  fragments  are  very  irregu- 
lar, with  their  angles  but  slightly 
rounded.  Most  of  them  are  very 
large,  the  smaller  ones  being  sev- 
eral feet  in  diameter.  One  of 
the  largest  is  four  miles  from  the 
source,  and  weighs  2000  tons. 

VI.  Age  of  the  Drift. — 1.  The 
absence  in  this  country  of  any 
deposits  of  the  periods  immedi- 
ately anterior  to  the  drift  agen- 
cy deprives  us  of  the  means  of 
comparison  with  such  deposits.  But  the  subsequent  deposits  of 
the  older  pleistocene 'enable  us  to  place  it  at  the  commencement 
of  the  grand  series  of  events  which  they  commemorate.  The 
older  pleistocene  is,  indeed,  so  intimately  connected  with  the  drift 
that  many  writers  have  failed  to  distinguish  the  two  periods. 

2.  We  have  before  remarked  that  the  dispersion  of  the  drift  of 
Northern  Europe  consisted  in  a  series  of  radiating  movements 
from  the  Scandinavian  center.  The  parallel  movements  of  the 
North  American  drift  must,  therefore,  have  had  a  different  origin, 
The  cote mporaneousn ess  of  the  two  agencies  is  not,  therefore,  to 
be  inferred  from  their  similarity  alone ;  proof  of  their  synchronism 
is  found  in  the  fact  that  each  immediately  preceded  the  pleisto- 
cene period.  It  has,  indeed,  been  stated  by  some  writers  that 
the  pleistocene  deposits  of  Northern  Europe  underlie  the  trans- 
ported blocks  of  the  drift.  But  all  the  unaltered  drift  of  those 
countries  is  found  by  those  geologists  who  have  made  it  a  special 
study  to  be  older  than  the  pleistocene. 


What  is  said  of  the  age  of  the  drift  in  this  country  ? 


136  .         aUATERNARY    SYSTEM. 

Probably  the  drift  of  the  northern  parts  of  Europe  and  01 
North  America  was  cotemporaneous  with  some  deposits  which 
have  been  referred  to  the  later  tertiary  of  Southern  Europe  and 
of  our  Southern  States. 

VII.  Theories  of  Drift. — The  great  problem — what  was  the 
agency  which  dispersed  the  drift,  and  wore  down,  smoothed,  and 
furrowed  the  rocky  floor  over  which  the  materials  moved — has  elic- 
ited many  theories.  We  shall  here  notice  the  outlines  of  these 
theories,  without  attempting  to  describe  all  their  modifications. 

1.  The  iceberg  theory  supposes  that  the  drift  country  was  sub- 
merged below  the  tops  of  the  mountains  not  long  before  the  drift 
agency,  and  that  a  polar  current  floated  down  icebergs  which 
were  loaded  with  the  materials  of  the  drift,  and  which,  melting 
during  their  progress  into  a  warmer  latitude,  strewed  the  drift 
along  their  course,  and  striated  the  rocks  at  the  bottom  of  the 
eea  by  the  fragments  which  were  frozen  into  them. 

This  theory  has  the  great  advantage  of  introducing  no  more 
violent  agencies  than  are  now  in  operation.  Such  a  polar  cur- 
rent now  exists,  bearing  icebergs,  some  of  which  are  loaded  with 
gravel,  into  warmer  regions.  If  this  country  were  submerged, 
the  polar  current,  which  now  has  a  strong  westerly  tendency, 
would  flow  over  a  large  part  of  the  drift  region.  The  hills  of 
gravel  are  such  as  would  be  produced  by  the  stranding  of  ice- 
bergs, either  dropping  their  freight  of  earth  and  stones,  or  crowd- 
ing up  the  materials  on  the  bed  of  the  sea,  and  as  they  were 
rocked  and  urged  on  by  the  waves. 

It  will  be  seen  that  this  theory  involves  both  submergence 
and  iceberg  agency. 

It  is,  however,  objected  to  the  theory  of  submergence  that  the 
drift  appears  to  be  entirely  destitute  of  fossils.  It  may  also  be 
objected  that  icebergs  could  not  have  taken  up  masses  of  rock 
from  submarine  valleys,  and  then  carried  them  over  the  mount- 
ains ;  that  on  the  tops  of  the  mountains,  rather  than  in  the  val- 

What  is  said  of  the  cotemporaneousness  of  the  American  and  European 
drift  ?  of  that  of  the  drift  and  later  tertiary  ?  What  is  the  iceberg  theory  1 
What  is  said  in  favor  of  this  theory  ?  What  is  said  against  it  ? 


ICEBERG    THEORY.  137 

leys,  the  scratches  should  more  frequently  octur,  but  this  is  not 
the  fact ;  that  the  source  of  the  materials  should  be  found  only  in 
higher  northern  latitudes,  whereas,  in  fact,  with  the  exception  of 
some  scattered  bowlders,  the  great  mass  of  the  materials  has  been 
removed  only  a  few  miles  ;  and  that  the  rocky  bed  of  the  ocean, 
especially  in  its  valleys,  would  have  been  more  or  less  protected 
by  a  covering  of  mud  from  the  furrowing  agency  of  stones  frozen 
into  the  icebergs. 

2.  The  theory  of  elevations  supposes  that  the  drift  countries 
were  submerged,  and  that  their  central  regions  were  subject  to 
violent  earthquakes  and  elevations,  oft  repeated  through  a  succes- 
sion of  ages  ;  that  these  convulsions  propelled  over  the  northern 
portions  of  the  globe  enormous  waves,  which  bore  along  the  im- 
mense icebergs  of  the  polar  regions,  and  strewed  the  pre-existing 
loose  materials  of  the  surface  far  to  the  south  of  their  former  po- 
sition ;  that  immense  masses  of  such  materials  received  a  portion 
of  the  impulse,  and  acted  on  the  rocks  beneath  in  the  same  man- 
ner as  glaciers. 

If  a  region  like  the  eastern  part  of  Iceland,  with  3000  square 
miles  of  ice  mountains,  were  exposed  to  such  earthquake  action, 
immense  numbers  of  icebergs  would  be  borne  along  by  the 
waves. 

In  support  of  this  theory,  it  is  argued  that  in  earthquake  waves 
there  is  an  actual  locomotion  of  the  water,  and  consequently  their 
momentum  must  have  been  inconceivably  greater  than  that  of 
ordinary  waves,  since  it  has  been  proved  that  a  current  of  twenty 
miles  per  hour  would  transport  stones  weighing  300  tons. 

It  is  also  said  that  we  may  thus  account  for  the  remarkable 
similarity  between  the  effects  of  the  drift  agency  and  those  of  the 
Alpine  glaciers  of  the  present  period. 

To  this  theory  it  is  objected  that  repeated  elevations  could  not 
go  on  long  enough  to  produce  the  drift  phenomena  before  the 
great  central  earthquake  region  would  have  been  elevated  above 
the  water. 

What  is  the  theory  of  elevations  ?  What  is  said  in  favor  of  this  -theory  ? 
What  is  the  first  objection  ? 


138  QUATERNARY    SYSTEM. 

Another  objection  to  this  theory  is  derived  from  the  fact  that 
an  immense  downward  pressure  and  almost  perfect  inflexibility 
of  the  striating  agents  are  demanded  by  the  phenomena.  While 
a  mass  of  mud,  sand,  pebbles,  and  bowlders  is  moving  in  a  liquid, 
the  upward  pressure  of  the  liquid  must  be  nearly  or  quite  equal 
to  the  downward  pressure  of  the  mass,  which  therefore  would 
exert  a  force  almost  wholly  in  a  horizontal  direction.  Nor  would 
the  pebblss  and  bowlders  be  held  in  a  fixed  position  with  that 
inflexibility  which  is  essential  to  the  production  of  drift  striae. 
Such  phenomena  as  we  have  described  on  p.  131  seem  to  indi- 
cate a  solid  agent. 

3.  The  glacier  theory  supposes  that  by  some  causes,  which  it 
does  not  profess  to  demonstrate,  a  refrigeration  of  the  climate 
covered  the  drift  region  with  glaciers,  and  at  length  with  a  vast 
glacial  sheet  several  thousand  feet  thick ;  that  in  Europe  the  cen- 
ter of  origin  was  in  the  Scandinavian  Mountains,  whence  the  gla- 
ciers proceeded  outward  in  all  directions,  increasing  until  they 
reached  the  limits  of  the  drift  agency ;  that  in  North  America 
the  glaciers  originated  in  or  near  the  Arctic  regions,  proceeding 
in  a  southerly  direction,  because  in  this  direction  only  were  they 
free  to  move,  and  increasing  until  they  formed  a  glacial  sheet 
5000  feet  thick ;  that  vicissitudes  of  climate  during  the  long  pe- 
riods of  drift  agency  caused  retreats  and  advances  of  the  glacial 
sheet  in  directions  not  exactly  coincident. 

It  has  been  objected  that  this  supposed  glacial  agency  of  the 
drift  period  differed  from  that  of  the  Alps,  inasmuch  as  the  latter 
is  limited  to  the  inclined  valleys  of  lofty  mountains,  and  that  the 
theory  does  not  account  for  the  origin  of  such  a  glacial  sheet. 
If  the  latter  objection  could  be  removed,  the  former  would  be 
irrelevant,  since  a  glacial  sheet  of  such  vast  extent  would  be  free 
to  move  only  outward,  as  the  Alpine  glaciers  are  now  free  to 
move  only  downward. 

It  has  been  attempted  to  account  for  the  origin  of  such  a  gla- 

What  other  objections  are  mentioned  ?  Describe  the  glacier  theory.  What 
objection  is  mentioned?  How  could  the  objection  be  removed?  What  is 
•aid  of  astronomical  causes  of  the  glacial  sheet  ? 


GLACIER    THEORY.  139 

cial  sheet  by  astronomical  changes,  which,  although  they  can  not 
be  disproved,  are  not  rendered  probable  by  any  known  facts  of 
the  same  kind.  Possibly  the  origin  may  be  found  in  geograph- 
ical changes,  as  a  great  elevation  of  the  land.  Such  elevation  is 
rendered  probable  by  the  descent  of  the  striae  beneath  the  ocean, 
and  by  the  transport  of  pebbles  across  regions  now  covered  with 
unfathomable  waters,  as  Massachusetts  Bay,  for  glaciers  never 
descend  into  the  sea.  If  now  these  entire  regions  were  elevated 
above  the  general  level  of  land  and  sea  as  much  as  some  mount- 
ain ranges  are,  they  would  be  covered  with  a  glacial  sheet.  Thus 
the  glacier  theory  furnishes  what  is  at  least  a  possible  cause  of 
the  origin  of  the  ice. 

Some  irrelevant  arguments  have  been  adduced  in  reference  to 
the  glacier  theory.  It  has  been  inferred,  from  the  discovery  of 
an  elephant  and  a  rhinoceros  in  the  ice  of  Siberia,  that  there  must 
have  been  a  great  and  sudden  change  from  a  temperate  to  a  frigid 
climate.  The  inference  may  be  correct,  but  evidence  is  yet 
wanting  that  the  event  occurred  during  any  part  of  the  drift 
period. 

The  argument  for  the  glacial  theory  is  founded  on  the  exact 
resemblance  between  the  effects  of  drift  agency  and  those  of  the 
Alpine  glaciers.  It  is  impossible  to  distinguish  these  effects  as  ex- 
hibited in  the  rounded  furrows  and  striated  surfaces  of  the  rocks. 
In  the  Alpine  regions  above  the  glacial  agency,  both  the  ledges 
and  fragments  of  rocks  are  angular,  in  marked  contrast  to  the 
rounded  rocks  below.  (See  Fig.  10.)  So  in  this  country,  the 
summit  of  Mount  Washington  has  only  angular  rocks.  Exam- 
ples similar  to  that  before  referred  to  on  page  128  (Fig.  32)  are 
found  in  the  Alps :  the  rolling  of  angular  stones  under  the  gla- 
ciers produces  similar  effects. 

Rocks  and  hills  which  have  been  in  the  path  of  Alpine  gla- 
ciers have  their  stoss  and  lee  sides.  The  loose  materials  are 

What  is  said  of  geographical  causes  ?  What  irrelevant  arguments  have  been 
adduced  ?  What  is  the  argument  in  favor  of  this  theory  derived  from  the  sur- 
faces of  the  rocks  ?  from  the  forms  of  rocks  and  hills  ?  from  the  distribution  of 
the  loose  materials  ? 


140  QUATERNARY    SYSTEM. 

crowded  forward,  while  there  is  a  tendency  in  the  glacier  to  go 
over  them,  so  that  they  are  not  moved  as  far  as  the  blocks  which 
are  imbedded  in  the  ice  or  which  lie  on  the  top  of  it.  (See  p. 
31,  Fig.  7.) 

A  glacial  sheet,  at  no  time  exceeding  5000  feet  thick  in  North 
America,  would  account  for  all  the  phenomena.  It  would  have 
almost  inflexibly  ascended  the  minor  inequalities  of  surface,  but 
have  been  deflected  from  its  course  by  lofty  mountain  ranges  and 
deep  valleys.  A  small  portion  of  a  glacier  has  no  perceptible 
flexibility,  while  that  of  the  whole  mass  is  so  great  that  they  have 
even  been  compared  to  viscid  bodies. 

VIII.  Fracture  of  Slate  Hills. — These  remarkable  phenomena 
are  generally  supposed  to  be  the  effects  of  drift  agency ;  but 
neither  the  time  nor  manner  of  their  origin  have  yet  been  con- 
clusively established. 

Most  of  the  examples  yet  known  in  this  country  occur  in  the 
southeast  part  of  Vermont.  The  layers  of  slate  stand  nearly  per- 
pendicular, but  on  the  hills  they  are  broken  and  inclined  from 
the  lines  of  fracture.  In  some  of  the  fractured  masses  the  lam- 
inae retain  their  former  relative  position,  without  any  intervening 
spaces.  Other  portions,  however,  have  been  broken  into  Ioos3 
fragments.  The  fractures  are  not  confined  to  the  tops  of  the 
hills,  but  in  at  least  one  instance  occur  at  the  base  of  a  small  hill. 
Fig.  37.  One  of  the  most  instructive  ex- 

amples was  found  in  Willard's 
quarry,  Guilford,  Vermont,  where 
the  top  of  a  hill  is  quarried  for 
roofing  slate.  The  most  conspic- 
uous part  of  the  dislocation  has 
been  exposed  by  quarrying,  and 
is  represented  in  the  accompany- 
ing figure,  of  a  vertical  surface  fac- 
ing south,  about  ten  feet  high. 

a  is  the  west  part  of  the  hill,  covered  with  drift ;  b,  slate,  the  lowest  part 
not  fractured,  the  rest  fractured ;  e,  loose  fragments  of  slate  thrown  over  to  the 
east  by  frost ;  c,  an  opening  made  by  quarrying. 

What  must  have  been  the  character  of  the  glacial  sheet?  What  is  said  of 
the  origin  of  the  fracture  of  slate  hills?  Where  do  most  of  the  examples  oc- 
cur? Describe  the  one  in  Guilford. 


ORIGIN    OF   THE    PLEISTOCENE.  141 

Fig  38.  The  strata,  not  being  free  to  yield  to  either 

side,  were  crushed  into  a  zigzag  position,  and 
are  quite  loose,  but  parallel.     Those  which 
have  been  left,  by  quarrying,  unsupported  on 
the  east  of  this  mass,  have  been  thrown  over  by  frost. 
The  zigzag  condition  of  the  fractured  yet  parallel  lay- 
ers, which  were  not  free  to  move  on  either  side,  in- 
contestably  points  to  some  force  acting  almost  direct- 
ly downward. 

The  accompanying  figure  exhibits  the  relations  of 
the  fractured  to  the  unfractured  strata  in  respect  of 
direction,  in  a  distance  of  seven  or  eight  miles  in  the 
southeast  part  of  Vermont. 

a  a  a  a,  direction  of  the  strata  in  each  locality,  A, 
B,  C,  D  ;  c,  direction  of  the  crushed  strata.     The  ar- 
rows indicate  the  direction  in  which  the  force  was  ex- 
erted, 
a 

SECTION  II.— PLEISTOCENE. 

The  name  of  this  formation  is  derived  from  two  Greek  words, 
•and  expresses  the  fact  that  most  of  the  fossils  belong  to  living 
spec  >es. 

I.  Lithological  Characters. — The  deposits  which  are  referred 
to  tbss  period  comprise  all  which  have  resulted  from  aqueous 
action  between  the  glacial  and  the  historical  periods.  Many  ge- 
ologists include  them  in  the  drift ;  and  no  small  part  of  the  dif- 
ferences of  opinion  on  theories  of  drift  has  been  caused  by  the 
confounding  of  the  glacial  and  aqueous  deposits  of  two  success- 
ive but  distinct  periods. 

I  he  pleistocene  deposits  in  this  country  are  altered  drift,  blue 
clay,  brown  clay,  fine  sand,  and  beds  of  marl. 

1.  Origin  of  the  Materials. — The  general  character  of  these 
deposits  will  be  better  understood  with  a  knowledge  of  their  ori- 
gin, which,  so  far  as  they  occur  in  drift  regions,  is  as  follows  : 

The  general  configuration  of  the  surface  of  the  country  having 
been  the  same  for  a  long  time  before  the  drift  period  as  at  pres 
ent,  the  streams  must  have  run  through  the  same  valleys,  and  had 

What  is  said  of  the  name  pleistocene?  What  is  included  in  this  period? 
What  are  the  deposits  ?  How  did  the  drift  agency  prepare  the  materials  ? 


142  QUATERNARY    SYSTEM. 

reduced  their  channels  to  a  level  not  very  different  from  the  pres- 
ent. The  drift  agency  then  drifted  the  enormous  amount  of 
loose  materials  which  had  been  accumulating  during  former  pe- 
riods, spread  them  over  the  surface,  and  more  or  less  filled  the 
valleys  and  blocked  up  their  outlets.  At  the  end  of  the  drift 
period,  and  during  the  earlier  parts  of  the  pleistocene  period,  a 
large  part  of  North  America  was  depressed  more  than  1500  feet, 
and  in  emerging  remained  for  a  long  period  at  400  or  500  feet 
below  its  present  level.  All  those  parts,  therefore,  which  have 
now  an  elevation  less  than  this  amount,  were  beneath  the  waters 
of  the  ocean. 

At  the  close  of  the  drift  period,  the  surface  of  the  drift  must 
have  contained  a  much  larger  proportion  than  at  present  of  fine 
materials.  These  were  washed  down  into  the  valleys,  from  which 
the  streams  removed  considerable  portions  to  the  ocean.  The 
particles  of  clay  being  much  finer  than  ^he  sands,  the  first  de- 
posits were  mostly  of  the  blue  clay.  The  long  continuance  of 
atmospheric  agency  converted  the  blue  into  brown  clay  in  the 
drift,  and  the  latter  deposits  are  accordingly  of  brown  clay  and 
brown  sand.  These  regular  deposits  of  clay  and  sand  are  most 
abundant  in  the  river  valleys,  whose  outlets  were  blocked  up ; 
and  in  ponds,  and  bays,  and  in  sounds  like  that  which  formerly 
extended  from  the  Gulf  of  St.  Lawrence  through  the  valley  of 
Lake  Champlain  to  New  York. 

While  the  characters  of  the  drift,  which  was  above  the  level  of 
the  pleistocene  seas,  were  modified  by  rains  and  streams,  and 
some  new  deposits  in  the  adjacent  waters  were  in  the  process  of 
formation,  the  action  of  the  waves,  tides,  and  currents  essential- 
ly modified  the  submerged  drift.  Hence  resulted  what  is  now 
called  altered  drift. 

In  order  to  understand  the  action  of  marine  agencies  on  the 
drift,  it  must  be  remembered  that  the  process  of  emergence  of 
the  land  has  been  very  gradual.  Each  part  has  been  successive- 

What  occurred  at  the  end  of  the  drift  period?  What  was  the  effect  of 
streams  on  the  drift  ?  of  atmospheric  agency  ?  of  the  pleistocene  seas  ?  Ho\» 
was  the  action  of  marine  agencies  prolonged  and  extended  ? 


ALTERED    DRIFT.  143 

ly  brought  nearer  the  surface  of  the  water,  and  subjected  to  ma- 
rine agencies  during  long  periods  of  time.  The  existence,  in  the 
valley  of  Lake  Champlain  and  elsewhere,  of  extensive  deposits 
of  clay  and  fine  sand,  which  have  now  a  well-defined  limit  of  400 
feet  above  the  sea  level,  indicates  a  long  stationary  period,  which 
interrupted  the  process  of  emergence. 

By  marine  agencies  the  submerged  drift  was  rearranged. 
The  outlines  of  its  surface  were  remodeled,  and  small  hills  and 
valleys  were  formed.  Most  of  the  pebbles  and  small  bowlders 
were  rolled  about  until  they  lost  their  drift  striae.  But  the  larger 
bowlders  more  frequently  retain  their  striae,  and  some  of  extra- 
ordinary size  probably  remain  in  their  original  position.  Small 
hills  of  altered  drift  and  cesars  (long,  narrow  ridges  of  loose  sand 
and  gravel)  were  formed  along  the  shores  by  the  action  of  waves 
and  tides. 

The  knolls,  or  small  hills  of  altered  drift,  are  common  near 
mountain  ranges.  In  Vermont,  in  the  valley  between  the  Ta- 
conic  and  Green  Mountains,  they  are  accumulated  in  groups,  at 
intervals  of  five  or  six  miles'  distance.  Some  of  them  are  150 
feet  high.  They  are  often  very  steep,  although  composed  of  ex- 
tremely loose  materials.  In  Hinesburg,  in  the  valley  of  Lake 
Champlain,  one  of  these  hills  is  3000  feet  long,  2000  feet  wide, 
and  300  feet  high. 

Fig.  39. 


HILLS    OF    PLEISTOCENE,  AMHERST,  MASS. 


What  were  the  particular  effects  ?     What  is  said  of  hills  of  altered  drift  T 


144 


QUATERNARY    SYSTEM. 


In  Amhsrst,  Massachusetts,  may  be  seen  a  group  of  hills  of  al- 
tered drift.  Fig.  39  represents  hills  of  altered  drift  in  the  east 
part  of  Amherst  Some  of  the  cavities  between  the  hills  are  oc- 
cupied oy  ponds  without  outlets.  They  are  evidently  the  effects 
of  marine  agency.  In  the  southeast  of  Massachusetts,  similar  ex- 
amples occur  at  a  distance  from  the  mountains.  Also  in  Berk- 
shire county,  on  the  east  side  of  Monument  Mountain. 

In  Andover,  Massachusetts,  there  are  oasars  of  unusual  length, 
Fig.  40.  These  ridges  are  situated  west  of  the  Shawsheen  River, 

Fig.  40. 


CESARS,  ANDOVER,  MASS. 

and  about  60  feet  above  it.  They  vary  from  15  to  30  feet  in 
height,  and  are  nearly  semi-cylindrical  in  form.  The  length  of 
east  ridge  is  one  mile  and  one  third ;  of  west  ridge,  one  mile  and 
three  quarters.  They  are  composed  of  sand,  smoothed  pebbles, 
and  bowlders.  Similar  ridges,  bowl-shaped  cavities,  and  round- 
ed hills  are  found  on  each  side  of  the  Shawsheen  for  several  miles. 
In  Sweden  cesars  are  common,  and  are  of  much  greater  length 
than  in  this  country. 

The  folio  wing  example  occurs  in  the  town 
of  Peru,  Vermont :  In  Fig.  41,  ?n  is  on  the 
east  side  of  a  north  and  south  range  of  hills; 
the  hill  at  m  is  about  150  feet  above  its  base, 
n,  but  rises  higher  to  the  west ;  a  is  the  south- 
west extremity  of  the  moraine,  which  here 
joins  the  hill  without  any  intervening  de- 
pression ;  at  N  it  terminates  abruptly,  hav- 
ing a  semicircular  form,  a  c  N.  The  top  va- 
ries but  little  from  a  level ;  the  total  length 
is  1000  feet ;  the  width  of  the  base  is  about 

What  is  said  of  oesars  in  Andover?  in  Sweden?     Describe  the  example  ir 


RIVER    TERRACES. 


145 


•ix  rods,  and  cf  the  top  from  three  to  six  yards.  It  consists  of 
loose  yellowish  brown  gravel  with  some  small  bowlders  ;  r  is  the 
turnpike. 

2.  Inter  stratification  of  Materials. — The  sands,  altered  drift, 
and  clays  of  this  formation  are  variously  interstratified,  and  thus 
indicate  local  changes  of  condition,  chiefly  in  respect  of  a  more  or 
less  violent  action  of  the  waters. 

The  following  section,  Fig.  42,  through  Fort  Greene,  at  Brook- 
lyn,  L.  I.,  shows  the  interstratification  of  fine  sand  and  altered 
drift.  Fine  blue  clay  often  takes  the  place  of  the  sand. 

Fig.  42. 


The  occurrence  of  numerous  bowlders  of  large  size,  in  irregu- 
larly stratified  masses  of  gravel  and  sand,  is  thought  by  some  ge- 
ologists to  indicate  the  agency  Df  icebergs. 

3.  River  Terraces. — The  materials  which  had  accumulated  dur- 
ing the  earlier  part  of  the  pleistocene  period  were  more  or  less 
rearranged  during  the  latter  part.  As  the  land  emerged  from 
the  ocean,  the  level  deposits  in  the  valleys  were  exposed. 
Through  them  the  rivers  then  excavated  channels,  and,  by  the 
gradual  lateral  shiftings  of  the  channels,  a  large  part  of  these  old- 
er pleistocene  deposits  were  removed  to  the  lower  levels  and  into 
the  sea,  while  the  margins  which  remain  constitute  the  existing 
terraces  of  river  valleys. 

In  general,  the  origin  of  river  terraces  may  be  described  as 
commencing  with  the  deposition  of  nearly  or  quite  horizontal 
plains  of  sand  and  altered  drift.  Flowing  through  these  level 
plains,  the  rivers  must  have  formed  serpentine  channels.  Conse- 
quently, by  increasing  the  convexity  of  the  bends,  and  then  cut- 

What  is  said  of  the  interstratification  of  materials  ?  of  the  origin  of  river  ter- 
races ?  of  the  action  of  rivers  on  the  pleistocene  deposits  ? 


146  QUATERNARY    SYSTEM. 

ting  them  off  or  wearing  away  their  headlands,  and  shifting  their 
beds,  they  removed  the  greater  portion  of  the  original  plain.  It 
is  not  necessary  to  suppose  that  the  distance  between  opposite 
terraces  is  any  indication  of  greater  magnitude  of  the  river  at  any 
former  time,  but  only  of  its  shifting  its  channel. 

The  process  having  advanced  thus  far,  we  have  an  intervale 
th/ough  which  the  river  flows;  and  if  the  channel  has  entirely 
cut  through  the  drift,  the  process  is  either  completed  or  so  much 
protracted  by  the  difficulty  of  wearing  down  the  solid  rocks,  that 
the  progress,  during  even  a  geological  period,  would  be  scarcely 
perceptible,  and  only  one  terrace  will  have  been  formed.  But  if 
a  terrace  has  been  formed  before  the  complete  removal  of  the  ob- 
structions in  the  channel,  the  same  process  must  have  been  re- 
peated within  the  new  and  narrower  level  of  intervale.  We 
should  thus  have  a  second  terrace.  Repetitions  of  the  process,  in 
cases  where  the  obstructions  were  not  entirely  removed,  would  oc- 
casion a  great  number  of  terraces.  On  some  streams  four  suc- 
cessive terraces  may  be  seen.  In  some  instances,  these  repeti- 
tions have  occurred  in  a  valley  in  which  several  streams  unite,  and 
the  changes  of  their  channels  have  left  not  only  many  terraces 
with  irregular  margins,  but  detached  portions,  like  islands,  in  a 
horizontal  surface  in  the  middle  of  the  valleys. 

In  the  mountainous  parts  of  the  New  England  States,  river 
terraces  occur  on  all  the  streams.  They  are  characterized  by  a 
nearly  horizontal  surface  jutting  out  from  a  hill  side,  or  extend- 
ing from  the  base  of  another  terrace,  with  an  irregular  line  of 
margin,  but  a  uniform  slope.  Irregularities  are  common,  and  are 
mostly  due  to  existing  agencies. 

In  Scotland,  also,  there  are  terraces  whose  materials  accumu- 
lated in  the  pleistocene  ocean,  and  which  have  been  formed  by 
subsequent  river  agency.  The  following  example  (Fig.  43)  oc- 
curs at  Dunkeld. 

a,  present  sea  level ;  1  b,  hills  forming  the  valley;  c  c,  their  ideal 
continuation ;  d  d,  the  terraces ;  efft  the  course  of  the  Bran  j  g, 
the  Tay ;  h,  Dunkeld. 

How  may  one  terrace  have  been  formed  ?  how  several  ?  What  is  said  of 
the  frequency  of  terraces  ?  of  terraces  in  Scotland  ? 


PLEISTOCENE    FOSSILS. 


147 


Fig.  43. 


4.  Marine  Terraces.  —  The 
prairie  terraces  of  Missouri  ter- 
ritory, as  the  Coteau  des  Prai- 
ries, have  no  communication  with 
rivers,  and  are  probably  the  lines 
of  ancient  sea  or  lake  coasts. 
Like  the  present  sea  and  lake 
coasts,  they  have  the  ground  at 
their  basis  strewn  with  blocks  of  stone.  In  Chili,  in  Barbadoes, 
and  in  Jamaica,  there  are  terraces  and  bluffs  near  and  often  par- 
allel to  the  present  sea-coast,  which  were  once  the  lines  of  coast, 
but  have  since  been  elevated  by  earthquakes. 

In  Scotland  and  in  Sweden,  marine  terraces  are  common  or 
hill  sides,  where  they  are  supposed  to  indicate  ancient  sea  levels 
In  the  following  example  in  Glen  Roy,  Scotland,  the  three  lines 
1,  2,  3  (in  Fig.  44),  represent  terraces  which  form  a  level  path- 
way along  both  sides  of  the  valleys,  with  little  interruption  for  five 
or  six  miles. 

Fig.  44. 


GLEN    ROY,   ACHXAVADDY,  SCOTLAND. 

II.  Topography  of  the  Pleistocene. — This  formation  occurs  in 
the  drift  regions  of  North  America  and  Europe.  In  South  Amer 
ica,  the  vast  plains  of  the  Pampas  consists  of  a  pleistocene  clay, 

What  is  said  of  marine  terraces  ?  Describe  the  example  in  Glen  Roy 
What  is  said  of  the  topography  of  the  pleistocene  ? 


148 


aUATERNARY    SYSTEM. 


which  has  been  explored  through  an  extent  of  200,000  square 
miles,  but  which  is  probably  two  or  three  times  larger.     A  part 
of  the  lowlands  of  the  Southern  States  of  this  country  is  pleisto 
cene.     Probably  the  vast  level  tundras  of  Northern  Siberia  are 
also  pleistocene. 

III.  Organic  Remains  of  tlie  Pleistocene. — 1.  The  organic  le- 
mams  of  this  period  in  North  America  consist  chiefly  of  the  shells 
of  Molluscs  and  the  bones  of  Mammalia. 

Of  the  marine  shells,  those  which  are  found  in  the  older  blue 
clays  are  pelagic.  Some  of  the  species  are  extinct.  One  of  the 
most  common  of  these  is  the  Nucula  Portlandica.  This  species 
Fig.  45.  occurs  in  the  valley  of  Lake  Champlain.  It 

is  abundant  in  the  vicinity  of  Portland,  Maine, 
in  company  with  several  other  shells,  such  as 
inhabit  rather  deep  water.  Nucula  Jacksonii 
(Fig.  45)  is  also  extinct.  It  occurs  at  Au- 
gusta and  in  other  parts  of  Maine. 

In  the  sands  which  overlie  the  blue  clays 
several  species  of  littoral  shells  occur  abund- 
antly, all  of  which  are  now  living  on  the  sea- 
shore.    The  most  common  is  Sanguinolaria  fusca  (Fig.  46),  arid 
Fig.  46.  Mya  arenaria,  the  long  clam.     Both  of  these 

species  occur  in  the  valley  of  Lake  Cham- 
plain,  in  the  same  position  in  which  they  died. 
Entire  beds  of  the  long  clam  occur  in  the 
same  perpendicular  position  in  which  this 
species  is  now  found  living  in  the  sandy  mud 
of  the  sea-shore. 

The  common  oyster,  Ostrea  borealis,  is  found  in  Maine,  far  in- 
land. It  occurs  also  at  Brooklyn,  New  York,  beneath  thick  beds 
of  gravel  and  bowlders,  with  numerous  other  marine  species,  all 
of  which  are  found  living  in  the  vicinity. 

Most  of  the  superficial  sands  and  gravel  in  the  Northern  States 
of  this  period  are  too  porous  for  the  preservation  of  fossils,  and 
hence  the  localities  are  few. 

In  the  lower  parts  of  the  Southern  States,  marine  shells  occur 

What  organic  remains  occur  in  North  America  ?  What  is  said  of  the  pela- 
gic (deep  water)  shells  ?  of  the  littoral  shells  ?  of  the  pleistocene  shells  of  the 
Southern  States? 


PLEISTOCENE    FOSSILS.  149 

in  some  superficial  strata  of  loose  materials,  which  were  deposit- 
ed during  this  period.  A  very  large  majority  of  the  species  in- 
habit the  neighboring  seas,  and  most  of  the  others  are  now  found 
in  the  West  Indies  and  the  Gulf  of  Mexico. 

The  marl  beds  occupy  basin-shaped  depressions,  which  were 
once  occupied  by  ponds,  or  they  occur  in  existing  ponds.  Many 
are  covered  with  beds  of  muck,  and  some  with  a  heavy  growth 
of  timber.  They  consist  of  fresh-water  shells  in  every  stage  of 
decay,  of  pulverulent  carbonate  of  lime,  which  has  probably  re- 
sulted from  a  complete  decay  of  the  shells,  and  of  a  variable  por- 
tion of  clay.  The  history  of  them  extends  into  the  historical  pe- 
riod, for  some  of  them  are  yet  in  the  process  of  accumulation. 

Fig.  47. 


SECTION    OF    PLEISTOCENE    AND    RECENT   DEPOSITS   IN    MONKTON    POND. 

In  the  accompanying  section  of  a  pond  in  Monkton,  Vermont, 
c  c  is  a  muck  bed,  encroaching  on  the  pond  n  n,  which  is  not  yet 
filled  up ;  e  e  is  the  bed  of  shell  marl,  more  than  ten  feet  thick ; 
o  o  is  a  bed  of  blue  clay.  The  shells  which  constitute  the  marl 
belong  to  species  which  are  now  living  in  the  pond. 

It  is  obvious  that  we  have  here  a  type  of  the  usual  process. 
First,  the  blue  clay  of  the  older  pleistocene  was  deposited  over 
drift ;  then  commenced  the  growth  of  the  mollusca,  which,  al- 
though for  the  most  part  less  than  one  quarter  of  an  inch  in  di- 
ameter, and  occupying  much  less  space  after  comminution,  have 
accumulated  to  the  amount  probably  of  300,000  cords,  or  more 
than  6,000,000,000,000  of  shells. 

Meanwhile  the  vegetable  deposit  commenced  not  far  from  the 
margin  of  the  pond,  and  is  now  advancing  into  it  over  the  marl, 
which,  however,  is  still  in  progress  ;  thus  showing  us  how,  of  two 
deposits  superimposed  the  one  on  the  other,  a  part  of  the  oldest 
portions  of  the  upper  one  may  be  more  ancient  than  the  newest 
part  of  the  lower  bed. 

The  length  of  the  pleistocene  period  is  strikingly  illustrated  in 

What  is  said  of  the  origin  of  marl  beds  ?     Describe  the  example  in  Monkton. 


150  aUATERNARY    SYSTEM. 

the  Monkton  marl  bed.  A  long  series  of  years  is  requited  to  fur- 
nish shells  sufficient  for  a  single  layer,  and  yet  they  have  accu- 
mulated to  more  than  ten  feet  in  depth.  20,000  years  is  a  very 
moderate  estimate  for  the  time  required  at  the  present  rate  of  ac 
cumulation,  and  it  is  more  likely  to  have  exceeded  this  many  fold. 
Yet  it  all  belongs  to  the  latter  part  of  the  pleistocene  period,  of 
which  it  is  probably  but  a  small  fraction. 

Those  parts  of  the  Southern  States  which  were  not  submerged1 
were  inhabited  by  an  extinct  species  of  horse,  of  bison,  hippopot 
amus,  elephant,  and  the  great  mastodon,  the  mylodon,  and  those 
huge  quadrupeds,  the  megatherium  and  megalonyx. 

It  was  probably  in  the  later  portion  of  the  pleistocene  period 
that  the  mastodon  flourished  in  great  numbers  in  the  Westen 
States,  and  wandered  as  far  to  the  northeast  as  the  Hudson  River. 
Their  skeletons  have  been  preserved  in  bogs  of  shell  marl  and  in 
the  salt  licks  of  the  West.  From  the  great  salt  lick  of  Kentucky 
the  bones  of  100  mastodons  have  been  removed,  with  those  of  the 
extinct  elephant  and  other  animals.  In  August,  1845,  was  found, 
in  Newburg,  New  York,  an  entire*  skeleton  of  the  great  Ameri- 
can mastodon  (Fig.  48),  with  the  head  raised  and  turned  to  one 

Fig.  48. 


NEWBURG    MASTODON. 


*  The  bones  of  one  foot  are  wanting,  and  are  supposed  to  have  been  car- 
ried away  in  the  marl,  which  was  removed  for  agricultural  purposes. 

What  is  said  of  the  length  of  the  process  ?     What  quadrupeds  inhabited  the 
Southern  States  ?     Where  did  the  mastodons  live  ? 


PLEISTOCENE    FOSSILS.  151 

sitter,  and  the  tusks  thrown  upward — the  posture  natural  to  a  quad- 
ruped when  sinking  in  the  mire.  The  stomach  was  also  found, 
containing  leaves  and  bruised  twigs,  as  had  been  seen  less  dis- 
tinctly in  some  previous  discoveries.  The  structure  of  the  teeth 
would  have  led  us  to  suppose  that  this  species  fed  on  the  boughs 
of  trees  and  on  young  saplings,  since,  differing  remarkably  from 
those  of  the  elephant,  the  grinders  are  covered  with  large  conic- 
al elevations,  which  must  have  enabled  them  to  grind  such  food 
with  great  facility  (see  Fig.  54,  page  156).  This  peculiar  form 
of  the  teeth  once  led  to  the  erroneous  idea  that  the  mastodon  was 
a  carnivorous  animal. 

The  remains  of  an  elephant  have  been  found  in  Vermont, 
where  the  Rutland  rail-road  crosses  the  Green  Mountains,  at  the 
bottom  of  a  deep  bed  of  muck. 

As  this  was  the  last  of  the  geological  periods  anteiior  to  oui 
own,  it  becomes  an  object  of  great  interest  to  form  some  conclu- 
sion respecting  the  time  when  these  gigantic  mammalia  flourished. 
In  the  more  northern  portion  of  their  range  they  are  found  to 
have  been  mired  in  shell  marl,  which  consists  of  the  same  species 
of  fresh- water  shells  which  now  inhabit  our  waters.  That  these 
quadrupeds  did  not,  however,  belong  to  the  present  period,  is 
obvious  from  the  condition  in  which  the  remains  are  found  under 
beds  of  muck.  Although  this  is  the  most  favorable  situation  for 
preserving  the  animal,  nothing  remains  but  the  bones.  But  the 
most  conclusive  fact  is  the  association  of  the  mastodon  with  many 
other  extinct  species.  The  Indian  traditions  of  living  mastodons 
are  doubtless  crude  geological  speculations,  founded  on  the  oc 
currence  of  the  bones. 

In  the  valley  of  Lake  Champlain,  in  Charlotte,  Vermont,  the 
skeleton  of  a  small  whale  has  recently  been  found.  It  was 
brought  to  light  by  a  rail-road  excavation  in  the  blue  clay.  This 
animal  resembled  the  Beluga,  or  white  whale  (Delphinapterus 
leucas),  which  now  inhabits  the  Northern  Sea.  It  was  13  feet 

What  is  said  of  the  Newburg  mastodon  ?  What  did  they  eat  ?  What  is 
said  of  their  teeth  ?  of  the  Vermont  elephant  ?  What  is  said  of  the  time  when 
tbese  mammalia  flourished  ?  What  is  said  of  the  white  whale  in  Vermont? 


152  QUATERNARY    SYSTEM. 

tf    4 

long.     Fig.  49  represents  the  remains  of  the  head,  which 


about  22  inches  long,  the  figure  being  one  sixth  of  the  natural 
size.     The  upper  jaw  had  16  teeth,  and  the  lower  jaw  had  14, 

Fig.  50. 


VERTEBRA. 
TEETH,  NATURAL  SIZE. 

Fig.  50.  That  the  tail  had  a  horizontal  fin  for  vertical  motion  is 
inferred  from  the  character  of  the  caudal  vertebrae.  It  is  obvious 
in  Fig.  51 ,  which  represents  them  as  seen  from  above,  that  these 
vertebrae  were  much  more  free  to  move  on  each  other  in  a  vert- 
ical direction  than  laterally.  This  figure  is  one  half  of  the  nat- 
ural size. 

From  the  shells  and  vegetable  remains  which  were  found  with 
the  skeleton,  it  may  be  inferred  that  the  water  was  at  least  a  few 


What  is  said  of  the  motion  of  the  tail  fin  ? 


PLEISTOCENE    FOSSILS. 


153 


fathoms  deep  when  the  animal  was  imbedded,  and  that  it  subse- 
quently became  a  salt  marsh. 

2.  South  America. — The  great  Pampean  formation  of  South 
America  contains  numerous  fossil  shells,  all  of  which  are  now  liv- 
ing in  the  neighboring  waters. 

Several  colossal  species  of  quadrupeds,  which  are  now  extinct, 
were  very  numerous  in  South  America.  Among  the  most  remark 
able  were  the  megatherium,  mylodon,  megalonyx,  and  scelido- 
therium,  some  of  which  had  bones  much  larger  than  the  elephant, 
although  the  entire  bulk  of  the  animals  was  not  greater.  The 
mylodon  and  megatherium  closely  resembled  in  their  structure 

Fig.  52. 


.5 


MYLODON   ROBUSTUS. 


What  is  said  of  the  place  in  which  the  skeleton  was  imbedded  ?  of  the  snelli 
of  the  Pampean  formation  ?  of  the  quadrupeds  of  South  America  1  of  the  hab- 
its of  the  mylodon  and  megatherium  ? 

G2 


154  aUATERNARY   SYSTEM. 

the  sloths,  that  feed  on  the  tender  twigs  of  trees,  which  they  climo 
for  this  purpose.  But  while  the  immense  size  of  these  extinct 
quadrupeds  prevented  them  from  imitating  their  modern  repre- 
st  ntatives  in  the  mode  of  obtaining  their  food,  their  size  and  pe- 
culiar structure  enabled  them,  by  tearing  down  the  trees,  to  bring 
their  food  within  reach. 

The  feet,  legs,  pelvis,  and  tail  of  the  mylodons  (Fig.  52,  p.  153) 
were  of  enormous  dimensions,  enabling  them,  as  they  rested  on 
the  firm  basis  of  their  massive  hind  legs  and  short  thick  tail,  to 
tear  down  large  trees,  whose  roots  they  may  have  loosened  by 
their  enormous  claws  and  fore  feet.  The  teeth  were  adapted  for 
chewing  only  the  tender  buds  and  leaves  of  trees.  They  had  only 
a  few  broad,  smooth  grinders,  the  front  of  the  mouth  being  desti- 
tute of  teeth.  For  chewing  twigs,  as  did  the  mastodons  of  North 
America,  more  uneven  surfaces  would  have  been  required.  Had 
their  food  been  on  the  ground,  incisors  in  the  front  of  the  mouth 
would  have  been  necessary. 

The  South  American  megatherium  (Fig.  53)  was  larger  than 
he  mylodon.  Its  length  was  eighteen  feet;  the  breadth  across 

Fig.  53. 


What  is  said  of  the  structure  of  the  mylodon  ?     Describe  the  megatherium 


PLEISTOCENE    MAMMALS.  155 

the  pelvis  was  six  feet,  and  the  opening  in  the  several  verte- 
brae for  the  passage  of  the  spinal  marrow  was  four  inches  in  di- 
ameter. The  tail  was  two  feet  in  diameter  in  the  upper  part. 
The  bones  of  the  legs  were  nearly  three  times  as  heavy  as  in  the 
largest  elephant,  and  the  foot  was  enormously  expanded,  so  as 
to  afford  a  firm  basis.  The  heel  bone  projects  backward  eight- 
een inches,  and  the  whole  foot  was  one  yard  long  and  two  thirds 
of  a  yard  wide.  Its  teeih  were  adapted  for  chewing  not  only 
the  tender  buds  and  leaves,  but  also  the  twigs  of  trees. 

The  existing  animals  of  this  tribe  are  liable  to  heavy  falls,  and 
their  dense  covering  of  soft  matted  hair  prevents  any  serious  in- 
jury. For  the  protection  of  the  brain,  the  outer  and  inner  plates 
of  the  skull  are  separated  by  an  unusual  thickness  of  air  cells,  so 
that  the  outer  one  may  even  be  broken  without  fatal  injury.  The 
heads  of  the  mylodon  and  megatherium  had  a  similar  structure, 
for  they  were  liable  to  similar  injuries  when  prostrating  trees. 

A  remarkable  confirmation  of  this  reasoning  occurred  in  the 
top  of  the  skull  of  a  mylodon.  The  outer  plate  of  the  skull  had 
been  broken  in  two  places,  one  of  which  was  entirely  and  the 
other  was  partially  healed.  The  animal,  therefore,  must  have 
survived  the  blows  which  caused  the  fractures.  It  must,  how 
ever,  have  been  stunned,  and  of  course  temporarily  disabled. 
The  carnivorous  animals  which  have  inhabited  South  America 
overcome  their  prey,  not  by  the  force  of  blows,  but  by  the  per- 
tinacity of  their  grasp,  and  could  not  inflict  such  wounds.  Nor 
is  it  likely  that  they  were  inflicted  by  any  of  the  huge  animals  of 
the  same  tribe,  since  the  habits  of  all  the  living  representatives 
are  remarkably  peaceful.  Nor  is  there  any  evidence  that  human 
beings  coexisted  with  the  mylodon.  Besides,  it  is  extremely 
improbable  that  any  living  adversary  inflicted  these  stunning 
wounds,  for  the  advantage  would  have  been  followed  up,  arid  the 
animal  would  not  have  escaped.  Nor  could  he  have  fallen  from 
a  precipice  in  that  region  of  plains ;  nor,  if  he  had,  would  he,  with 

To  what  accidents  are  the  living  animals  of  this  tribe  liable  ?  To  what 
were  the  mylodon  and  megatherium  exposed  ?  What  is  said  of  a  fractured 
and  healed  skull  of  a  mylodon  ? 


156 


QUATERNARY    SYSTEM. 


a  proportionately  very  small  head,  have  fallen  upon  it.  It  only 
remains,  therefore,  to  ascribe  the  wounds  to  falling  trees,  and  ac- 
cordingly the  fissures  of  the  fractured  skull  proceed  from  a  Ion 
gitudinal  wound,  not  from  a  central  depression. 

3.  During  the  same  period,  also,  there  lived  in  Great  Britain 
and  on  the  continent  of  Europe,  many  quadrupeds,  most  of  which, 
including  all  the  larger  species,  are  extinct ;  as  a  species  of  ele- 
phant, of  bear,  and  of  hyena,  larger  than  any  now  living ;  of  horse, 
lion,  tiger,  &c.     Great  numbers  of  the  remains  of  the  elephant 
are  in  the  shallow  parts  Df  the  German  Ocean,  and  in  the  gravel 
beds  of  England.     These  occur  with  some  animals  which  may 
have  become  extinct  since  the  existence  of  man,  as  the  great 
Irish  elk ;  and  with  others,  which  are  yet  in  existence,  as  the  fox 
and  wolf.     Thus  it  appears  that  the  extinction  of  species  of  that 
epoch  was  a  gradual,  and  not  a  sudden  and  violent  process. 

4.  Probably,  also,  the  gigantic  birds  of  New  Zealand  existed 
during  the  same  period,  although  continued  into  the  historical 
epoch. 

5.  In  the  pleistocene  of  Northern  Asia,  the  bones  of  mammoths 
occur  in  immense  quantities.     Sometimes  they  are  found  mixed 
with  bones  of  extinct  species  of  rhinoceros,  ox,  horse,  antelope. 


TEETH   OF   THE    MASTODON    AND    ELEPHANT. 


What  is  said  of  the  European  quadrupeds  ?  of  the  birds  of  New  Zealand  ? 
of  the  animals  of  Northern  Asia? 


PLEISTOCENE    MAMMALS.  157 

&c.,  and  even  with  the  remains  of  marine  animals.  Rarely  they 
occur  with  shells  and  corals  attached  to  them. 

The  mammoth  belonged  to  the  same  genus  with  the  two  ex- 
isting species,  the  Indian  and  the  African  elephant.  But  the 
mastodons  constituted  a  separate  genus,  which  is  wholly  extinct. 

The  most  characteristic  peculiarities  of  these  two  genera  may 
be  seen  in  the  preceding  figures  of  their  teeth,  Fig.  54. 

In  less  obvious  but  important  peculiarities  of  the  teeth  and 
JAWS,  the  mammoth  differed  from  the  existing  elephants.  The 
tusks  were  very  large  and  curved  backward,  forming  almost  a 
circle,  Fig.  55.  It  was  well  clothed  with  thick-set  curly  hair. 

Fig.  55. 


ELEPHAS    PRIMOGENIUS. 

The  abundance  of  mammoth  bones  in  Siberia  is  remarkable. 
In  as  high  latitudes  as  65°  north,  in  Siberia,  wherever  a  rivei 
undermines  its  banks,  bones  are  dislodged.  The  tusks  furnish 
a  large  portion  of  the  ivory  which  is  used  in  the  arts. 

Even  as  far  north  as  latitude  75°,  there  is  in  the  Polar  Sea, 
longitude  140°  east,  an  island,  Kotelno,  north  of  Siberia,  where 
the  hills  of  the  interior  contain  the  bones  of  horses,  buffaloes, 
oxen,  and  sheep,  in  such  abundance  as  to  show  that  these  ani- 
mals formerly  lived  there  in  numerous  herds. 

What  is  said  of  the  difference  between  the  mammoths  and  the  mastodons  t 
What  is  said  of  the  form  of  mammoth  tasks?  of  their  abundarce?  What  i* 
said  of  quadrupeds  north  of  Siberia  ? 


*8  QUATERNARY    SYSTEM. 

The  mammoth,  of  the  skeleton  of  which  the  preceding  figure  is 
a  representation,  was  found  entire,  preserved  in  ice.  It  was  first 
seen  in  1799,  by  a  fisherman  who  was  in  the  habit  of  searching 
along  the  shores  of  the  Arctic  Ocean  for  tusks.  It  was  then  en- 
veloped in  blocks  of  ice,  but  in  1801  a  part  of  it  was  fairly  ex- 
posed to  view,  and  in  1803  the  ice  melted,  so  that  the  enormous 
carcass  fell  upon  a  bank  of  sand.  In  1804  the  discoverer  cut  off 
the  tusks,  which  weighed  360  pounds,  and  sold  them.  Meanwhile 
the  people  in  the  vicinity  used  the  flesh  to  feed  their  dogs  during 
a  time  of  scarcity.  White  bears,  wolves,  and  foxes  also  fed  upon 
it.  In  1806  it  was  found  by  Mr.  Adams,  who  was  in  the  service 
of  the  Emperor  of  Russia,  and  the  remains  were  removed  to  St, 
Petersburg. 

When  found  by  Adams,  the  skeleton  was  entire  with  the  ex- 
ception of  one  fore  leg.  The  skin  of  the  head  and  even  the  eyes 
remained,  and  one  of  the  ears  with  a  tuft  of  hair.  About  three 
fourths  of  the  skin  was  found,  covered  with  reddish  wool  and 
blackish  hair,  about  one  and  a  half  inches  long.  The  carcass  was 
nine  feet  four  inches  high,  and  sixteen  feet  four  inches  long,  not 
including  the  tusks.  These  were  nine  and  a  half  feet  around 
the  curve,  and  only  three  feet  seven  inches  from  base  to  point. 
Much  of  the  hair  had  been  trodden  into  the  ground  by  the  white 
bears,  yet  thirty-six  pounds  of  it  were  collected. 

This  skeleton  is  now  in  the  museum  of  the  Academy  of  St. 
Petersburg. 

IV.  Age  of  tlie  "Pleistocene  Period. — In  the  drift  regions  of 
North  America  and  Northern  Europe,  the  duration  of  the  pleis- 
tocene period  is  well  defined  geologically,  as  comprising  the  in- 
terval between  the  drift  and  the  historical  period.  The  com- 
mencement of  the  formation  dates  at  the  dissolution  of  the  gla- 
ciers and  the  submergence  of  the  land.  In  other  regions,  the 
commencement  is  indicated,  with  sufficient  accuracy,  by  the  in- 

In  what  situation  was  the  mammoth  found  entire  ?  What  use  was  made 
of  its  flesh?  What  was  its  condition  when  found  by  Mr.  Adams?  How  ia 
the  duration  of  the  pleistocene  defined  ?  What  is  said  of  the  time  of  its  com- 
mencement ? 


AGE    OF    THE    PLEISTOCENE.  159 

troduction  of  the  marine  shells,  which  were  associated  with  the 
extinct  quadrupeds,  but  which,  with  few  or  no  exceptions,  have 
survived  to  the  present  time.  The  end  is  marked  in  all  countries 
where  deposits  are  found  by  the  extinction  of  the  numerous  spe- 
cies of  huge  quadrupeds,  which  most  distinctly  characterize  the 
latter  part  of  the  period. 

The  synchronism  of  the  deposits  in  different  countries  is  estab- 
lished with  sufficient  accuracy  by  the  fact  of  the  association  of  the 
extinct  quadrupeds  with  shells,  of  which  few  or  none  are  extinct, 
or  even  by  such  shells  alone. 

In  the  Southern  States,  and  probably  also  in  Southern  Europe, 
the  limits  of  the  pleistocene  period  are  not  so  well  denned  as  in 
the  drift  regions.  There  appears  to  have  been  an  uninterrupted 
series  of  similar  events  from  the  tertiary  to  the  historical  period. 
These  events  consisted  chiefly  in  the  very  slow  changes  of  sea 
levels,  in  the  gradual  extinction  of  a  very  small  minority  of  the 
molluscs,  and  in  the  entire  extinction  of  the  vertebrated  animals. 

It  follows  that  the  pleistocene  of  the  drift  regions  should  be  as- 
sumed as  the  fixed  point  in  investigating  the  age  of  other  pleis- 
tocene deposits. 

The  absolute  duration  of  this  period  is  not  easily  estimated 
In  the  Falls  of  Niagara  we  have  a  rude  but  grand  natural  chro- 
nometer for  the  latter  part.  There  is  good  reason  to  believe  that 
before  the  drift  period  the  Niagara  River  followed  a  direct  course 
to  St.  David's,  and  that  its  channel  was  filled  during  the  drift  and 
older  pleistocene  period  with  bowlders,  clay,  &c.  Since  its 
emergence  from  the  older  pleistocene  seas,  it  has  excavated  the 
channel  from  Queenstown  to  the  present  falls.  The  rate  of  re- 
trocession at  the  present  time  is  pretty  well  known ;  and  although 
it  must  have  varied,  some  positions  being  more  and  others  less 
easily  cut  through,  the  time  since  its  emergence  is  inferred  to  be 
not  less  than  30,000  to  40,000  years.  This  is  probably  but  a 
small  portion  of  the  entire  pleistocene  period. 

What  is  said  of  the  end  of  the  period  ?  of  the  synchronism  of  deposits  in  dif- 
ferent countries  ?  of  the  limits  of  the  period  in  the  Southern  States  ?  of  the 
Falls  of  Niagara? 


160  (QUATERNARY    SYSTEM. 

It  is  a  remarkable  fact,  that  the  species  of  the  mollusca  havo 
outlived  the  quadrupeds  of  the  pleistocene  period.  Yet  the  du- 
ration of  quadruped  races  comprises  a  longer  series  of  events  than 
has  elapsed  since  the  creation  of  man.  We  have  seen,  too,  that 
a  small  part  of  the  life  of  the  pleistocene  mollusca  measures  30,000 
or  40,000  years.  Yet  there  has  been  but  a  very  slight  change  in 
the  species  from  the  commencement  of  that  period  to  the  present 
day.  But  the  older  formations,  of  which  there  are  several  hund- 
red, are  distinguished,  for  the  most  part,  each  by  very  many  pe- 
culiar species  of  shells.  Consequently,  the  duration  of  each  of 
the  periods  of  the  older  formations  must  have  far  exceeded  tho 
whole  time  which  has  elapsed  since  the  beginning  of  the  pleis- 
tocene. 

V.  Geography  of  tlie  Pleistocene  Period. — The  geography  of 
this  period  is  susceptible  of  more  complete  description  than  that 
of  any  previous  period,  for  each  geological  formation  has  been 
made  at  the  expense  of  the  pre-existing  formations.  Hence  the 
present  limits  of  the  older  formations  afford  comparatively  mea- 
ger information  on  the  distribution  of  land  and  water,  and  de- 
pendence is  placed  more  exclusively  on  the  characters  of  their 
organic  remains  and  of  the  materials  deposited.  But  here  we 
have,  in  addition,  the  scarcely-altered  deposits  of  ancient  seas, 
and  the  marks  of  ancient  sea  levels  over  regions  of  which  the  in- 
equalities of  surface  were  nearly  the  same  as  at  the  present  time 

Fig.  56. 
___  _/T _________ 


A 
/ 


IDEAL    SECTION    OF    NEW    ENGLAND. 


What  is  said  of  the  comparative  longevity  of  the  species  of  mollusca  and  of 
quadrupeds  ?  What  is  the  inference  respecting  the  older  formations  ?  What 
.«  said  of  the  geography  of  the  period? 


GEOGRAPHY    OP    THE    PLEISTOCENE    PERIOD.  161 

The  preceding  figure  exhibits  the  relations  of  land  and  water 
during  this  period  in  the  New  England  States. 

A  B.  Green  Mountains ;  C.  Mt.  "Washington ;  a.  Upper  limit 
of  the  drift  agency  ;  b.  Lake  Champlain.  1.  Sea  level  during  the 
drift  period  ;  2.  Sea  level  at  the  beginning  of  the  pleistocene  pe- 
riod ;  3.  Sea  level  stationary  during  a  part  of  the  pleistocene  pe- 
riod ;  4.  Sea  level  at  the  present  time. 

Of  the  different  sea  levels,  No.  2  was  more  than  1500  feet 
above  the  present  level  of  the  sea;  consequently,  most  of  the  con- 
tinent was  beneath  the  ocean,  and  the  parts  which  are  now  mount- 
ainous constituted  groups  of  islands.  No.  3  has  been  ascertain- 
ed to  have  been,  in  the  valley  of  Lake  Champlain,  400  feet  above 
No.  4,  the  present  sea  level.  In  the  valley  of  the  St.  Lawrence 
it  is  said  to  have  been  100  feet  higher.  Probably  much  of  the 
eastern  part  of  North  America  was  submerged  to  this  depth  for 
a  long  time.  A  necessary  consequence  was,  that  New  England 
and  New  Brunswick  constituted  a  large  island.  This  was  sep- 
arated from  the  main  land  of  New  York  by  a  strait,  which  ex- 
tended from  the  valley  of  the  St.  Lawrence  through  the  valley 
of  Lake  Champlain,  of  the  Champlain  Canal,  and  of  the  Hudson 
River.  The  summit  level  of  the  canal  indicates  the  most  shal- 
low part  of  this  strait,  which  had  a  depth  of  about  125  feet.  The 
western  part  of  Vermont  was  thickly  studded  with  small  islands 
in  a  tranquil  sound.  The  exterior  portions  of  the  New  England 
States,  and  extensive  districts  in  the  Middle  States,  constituted  a 
beautiful  archipelago  of  small  and  picturesque  islands. 

By  a  depression  of  the  low  land  of  the  Southern  States,  the 
Gulf  Stream  may  have  flowed  over  them,  and  the  Gulf  of  Mex- 
ico have  covered  a  much  larger  area.  Subsequently,  however, 
more  or  less  of  the  Southern  States  has  been  more  elevated  than 
at  present. 

The  vast  plains  in  South  America,  which  we  have  mentioned 
as  a  pleistocene  deposit,  were  submerged  during  this  period. 
The  fine  mud  of  the  great  Pampean  formation  indicates  the  per- 

Describe  Fig.  56.  What  was  the  condition  of  this  continent?  What  large 
island  in  North  America  at  a  later  part  of  this  period?  What  is  said  of  the 
Southern  States?  of  South  America? 


162  QUATERNARY    SYSTEM. 

feet  repose  of  the  waters.  The  subsequent  process  of  emergence, 
protracted  through  long  periods  of  time  to  the  present  era,  is  ex 
hibited  in  the  terraced  plains  which  are  seen  at  successively  low 
)r  levels  in  approaching  the  sea. 

In  Northern  Europe  the  general  series  of  events  was  similai 
to  that  of  North  America.  The  accompanying  section  (Fig.  57) 
represents  the  different  sea  levels  in  Scandinavia.  A  consider 
able  portion  of  Northern  Europe  must  have  been  submerged. 
There  is  evidence,  also,  that  during  another  epoch  in  this  period 
Great  Britain  was  elevated  to  a  greater  height  than  at  present, 
and  that  much  of  the  adjacent  seas  was  dry  land. 

Fig.  57. 


1 1.  Limit  of  glaciers. 

Ist.lst.  Sea  level  at  the  commencement  of  the  drift  period. 

2d.  2d.  Sea  level  .in  the  pleistocene  period. 

3d.  3d.  Present  sea  level. 

The  basin  of  the  Caspian  Sea  was  much  larger,  and  commu- 
nicated with  the  Black  Sea.  A  large  part  of  North  Siberia  was, 
during  a  part  of  the  period,  covered  by  the  Arctic  Ocean.  This 
submergence  may  have  occurred  in  the  latter  part  of  the  period, 
subsequently  to  that  of  the  drift  regions  in  Europe  and  North 
America. 

Since  the  numerous  islands  of  Polynesia  have  been  gradually 
sinking  beneath  the  waters  of  the  Pacific  during  the  present  pe- 
riod, and  perhaps  for  a  longer  time,  it  follows  that  during  the 
pleistocene  period  there  was  a  greater  extent  of  la^id  in  those 

What  is  said  of  Northern  Europe?  of  Great  Britain?  of  the  Caspian  Sea? 
of  Siberia?  of  Polynesia? 


CLIMATE    OF    THE    PLEISTOCENE    PERIOD.  163 

regions  than  at  the  present  tirre.  Either  during  that,  or  in  some 
more  remote  period,  the  immense  area  of  Polynesia  may  have 
been  occupied  with  a  continent,  the  mountains  of  which  consti- 
tute the  present  groups  of  islands. 

It  is  obvious  that  the  extent  of  submergence  appears  on  a  sub- 
sequent emergence  of  the  land.  It  is  far  more  difficult  to  ascer- 
tain what  regions  which  are  now  beneath  the  sea  may  have  beeu 
dry  land  during  the  pleistocene  period. 

We  have  seen  now  that  extensive  regions  on  both  continents 
were  above  and  below  the  level  of  the  sea  in  different  parts  of 
this  period.  There  is  no  reason  to  suppose  that  these  events  oc 
curred  any  more  rapidly  than  similar  events  now  take  place. 
Thus  the  history  of  one  period,  which  is  probably  of  much  shorter 
duration  than  any  of  more  ancient  date,  comprises  an  immensity 
of  time,  which  the  mind  fails  to  comprehend. 

VI.  Climate  of  the  Pleistocene  Period. — The  pleistocene  climate 
of  North  America  does  not  appear  to  have  differed  in  its  mean 
temperature  from  its  present  climate.  The  marine  shells  which 
occur  in  our  older  clays  have  been  supposed  by  some  European 
writers  to  belong  to  species  which  are  exclusively  Arctic.  But 
they  are,  for  the  most  part,  identical  with  species  which  now  ex- 
ist abundantly  on  the  shores  of  New  England,  as  well  as  fur- 
ther north.  They  therefore  indicate  merely  the  influence  of  a 
polar  current,  similar  to  that  which  now  chills  the  waters  of  our 
coast. 

It  is  probable,  therefore,  that  the  Labrador  current,  which 
even  now  has  a  westwardly  tendency  into  the  Gulf  of  St.  Law- 
rence, chilled  the  waters  which  covered  the  lower  parts  of  Can- 
ada and  New  England.  On  the  other  hand,  it  is  probable  that 
the  Gulf  Stream  flowed  over  the  lower  parts  of  the  Southern 
States.  By  these  agencies  the  shells  now  inhabiting  Massachu- 
setts Bay  and  the  Gulf  of  Mexico  were  mingled  in  the  basin  of 
the  Potomac.  The  waters,  at  least,  of  the  Southern  States  were 
warmer  than  at  present,  so  as  to  be  inhabited  by  species  of  shells 
which  now  occur  only  in  the  Gulf  of  Mexico  and  the  West  In- 
dies. 

The  existence  of  elephants  in  Vermont  does  not  necessarily 
indicate  a  warmer  climate,  since  the  species  may  have  had  a 

What  is  said  of  the  time  required  for  the  changes  of  level  ?  What  was  the 
climate  of  North  America  during  the  pleistocene  period  ? 


164  TERTIARY    PERIOD. 

clothing  like  that  of  the  Siberian  elephant.  A  structure  and 
habits  adapted  to  the  climate  of  the  Northern,  and  Middle,  and 
Western  States  would  have  required  only  specific  peculiarities 
in  which  it  should  have  differed  from  the  existing  species  of  the 
same  genus. 

So  also  the  elephants,  which  inhabited  Great  Britain  and  the 
continent  of  Europe,  prove  no  essential  difference  of  climate. 
The  uniform  and  mild  climate  which  now  characterizes  Western 
Europe  may  have  been  extended  further  eastward  by  the  sub- 
mergence of  large  portions  of  land. 

In  Siberia,  the  immense  numbers  of  the  remains  of  elephants 
do  not  prove  the  climate  to  have  been  tropical,  for  the  species 
was  furnished  with  a  woolly  covering.  But  the  climate  of  North- 
ern Siberia  must  have  been  much  milder  than  it  now  is,  in  order 
to  the  production  of  a  vegetation  required  by  the  numerous  herds 
of  mammoths. 

In  South  America,  the  pleistocene  climate  appears,  from  the  fos- 
sil shells,  to  have  been  the  same  as  at  the  present  time. 


CHAPTER  V. 
TERTIARY   PERIOD. 

THE  next  chapter  in  these  ancient  records,  to  the  investigation 
of  which  we  now  proceed,  contains  the  history  of  the  Tertiary 
Period.  The  rocks  of  this  period  underlie  the  drift,  and  must 
therefore  have  been  deposited  previous  to  any  hitherto  described. 

1.  Geographical  Distribution. —  The  tertiary  of  the  United 
States  is  found  upon  the  Atlantic  sea-board  and  the  Gulf  of  Mex 
ico.  Its  western  limit  is  at  the  first  or  lowest  falls  of  the  princi 
pal  rivers,  and  is  generally  marked  by  the  long-leaved  pine  (Pinus 
palustris),  whose  distance  from  the  shore  is  limited  by  this  for- 
mation. In  South  America,  according  to  M.  D'Orbigny,  ter- 
tiary rocks  extend  from  the  great  plains  of  the  Amazon  to  the 
Straits  of  Magellan,  a  distance  of  2500  miles,  with  a  width  in 
many  places  of  800  miles. 

What  is  said  of  the  climate  of  Europe  ?  of  Siberia  ?  of  South  America  9 
How  is  the  tertiary  distributed  ? 


CLASSIFICATION    OP    THE    TERTIARY.  165 

In  Europe  and  Asia,  the  rocks  of  this  period  are  found  princi- 
pally in  basins,  apparently  deposited  in  lakes  and  estuaries  of 
limited  extent. 

2.  Composition  and  Structure. — The  tertiary  rocks  consist  of 
numerous  layers  of  marls,  clays,  sandstones,  and  limestones,  which 
generally  lie  in  nearly  a  horizontal  position,  and  are  often  con- 
solidated into  a  hard,  compact  rock.     Most  of  the  rocks  are  filled 
with  the  remains  of  marine  or  fresh-water  shell-fish,  land  animals, 
and  vegetables,  which  more  or  less  resemble  existing  species; 
while  scoria  and  streams  of  lava  have  in  many  cases  become  min- 
gled with  the  sedimentary  deposits. 

3.  Classification  of  the  Tertiary. — This  system  has  been  divi- 
ded by  Sir  Charles  Lyell  into  four  groups,  founded  upon  tlue  pro- 
portion of  living  to  extinct  species  of  shells  which  they  contain. 

(1.)  The  oldest  or  lowest  group  is  called  Eocene,  the  dawn  or 
commencement  of  the  existing  types  of  animals  and  plants,  and 
contains  about  four  per  cent,  of  shell-fish  now  living. 

(2.)  The  second  group  is  called  Miocene  (less  recent),  and  con- 
tains about  20  species  in  100  of  shell-fish,  which  are  identical  with 
those  now  living  in  the  adjacent  lakes  and  seas. 

(3.)  The  third  and  fourth  groups  are  called  Older  and  Newer 
Pliocene  (more  recent),  and  contain  from  50  to  90  species  in  100 
of  existing  shells.  These  may  be  described  as  one  group.  We 
shall  then  have  the  Pliocene  or  Newer  Tertiary,  the  Miocene  or 
Middle  Tertiary,  the  Eocene  or  Older  Tertiary. 

This  classification  applies  to  the  European  better  than  to  the 
American  tertiaries.  The  eocene  of  Virginia,  South  Carolina, 
and  Alabama  does  not  contain  a  single  recent  shell,  and  yet  it  is 
probably  cotemporaneous  with  the  European  eocene. 

It  is,  moreover,  doubtful  whether  the  American  tertiaries  can 
be  classified  so  as  to  make  three  groups.  There  seem  to  be  but 
two  periods,  and  those  in  the  northern  part  of  the  United  States 
appear  to  correspond  with  the  eocene  and  miocene,  and  in  the 

What  is  its  composition  and  structure  ?  Mention  the  principle  of  classifies 
ti  »n  and  the  divisions  .of  the  tertiary.  How  does  this  classification  apply  to 
the  American  continent  ? 


166  TERTIARY    PERIOD. 

southern  portions  to  eocene  and  pliocene.  It  is  probable  that 
the  miocene  and  pliocene  periods,  so  distinctly  marked  in  Europe, 
constitute  but  one  period  in  the  United  States,  so  that  it  is  difficult 
to  determine  the  exact  synchronism  of  the  deposits  on  the  two 
continents. 

SECTION  I.— PLIOCENE  OR  NEWER  TERTIARY. 

It  would  be  impracticable  in  an  elementary  treatise  to  describe 
all  the  deposits  included  in  this  division  of  the  tertiary.  A  few 
examples,  selected  from  American  and  European  pliocene,  will 
suffice  to  illustrate  its  character,  and  the  nature  of  the  mineral 
and  organic  changes  which  occurred  during  this  part  of  the  ter- 
tiary period. 

1.  Pliocene  of  the  United  States.     1.  Distribution. — The  plio- 
cene of  the  United  States,  according  to  Professor  Tuomey,  is 
confined  to  the  Atlantic  sea-board.     The  deposits  are  found  in 
patches  from  Maryland  to  Georgia,  but  slightly  elevated  above 
the  sea  level. 

2.  Composition. — The  pliocene  is  composed  mostly  of  yellow- 
ish sands  and  marls,  which  vary  in  thickness,  but  rarely  exceed 
40  feet.     The  strata  are  arranged  in  nearly  horizontal  layers,  and 
repose  mostly  on  the  older  eocene,  or  on  cretaceous  rocks.     The 
marl  contains  a  large  proportion  of  carbonate  of  lime,  and  great 
numbers  of  fossil  shells. 

3.  Geological  Position. — Although  these  rocks,  in  South  Car- 
olina and  Georgia,  contain  a  very  large  proportion  of  recent 
shells,  similar  deposits  in  Maryland  and  Virginia,  from  the  larger 
proportion  of  extinct  species,  have  been  referred  to  the  miocene. 
The  number  of  fossil  shells  identical  with  existing  species  con- 
stantly increases  in  going  from  the  northern  to  the  southern  por- 
tions of  strata,  which  appear  to  belong  to  the  same  period,  and 
the  proportion  of  carbonate  of  lime  also  increases;  but  the- tran- 
sition is  not  sufficiently  marked  to  enable  us  to  separate  those 
deposits  which  were  made  during  the  pliocene  from  those  which 

How  is  the  pliocene  of  the  United  States  distributed?     What  is  its  compo- 
sition ?  its  geological  position  ? 


AMERICAN    AND    EUROPEAN    PLIOCENE.  167 

belong  to  the  miocene  period.  Professor  Tuomey  has  referred 
the  South  Carolina  beds,  which  rest  upon  the  eocene,  to  the 
pliocene.  With  this  exception,  and  a  few  other  deposits,  as  one 
at  the  mouth  of  the  Potomac,  these  rocks,  from  the  proportion  of 
recent  to  extinct  shells,  would  be  referred  to  the  older  pliocene 
of  Mr.  Lyell ;  but  as  they  repose  upon  the  eocene,  they  may, 
with  more  propriety,  perhaps,  be  described  with  the  miocene. 

II.  European  Pliocene.  —  1.  TJie  NorwicJi  or  Mammalif&rous 
Crag  of  England  belongs  to  this  period.  It  is  composed  of 
shelly  beds  of  sand  and  loam,  deposited  at  the  mouth  of  a  river, 
and  filled  with  the  remains  of  several  species  of  mammalia ;  hence 
its  name.  Other  strata,  which  overlie  the  crag,  appear  to  have 
Deen  deposited  in  a  fresh-water  lake,  and  contain  also  the  re- 
mains of  mammalia. 

But  the  best  examples  of  the  pliocene  strata  occur  in  the 
south  of  Europe,  on  the  shores  of  Italy,  Sicily,  and  on  many  of 
the  islands  of  the  Eastern  Archipelago. 

2.  The  Val  di  Noto,  lying  between  .ZEtna  and  the  southern 
promontory  of  Sicily,  consists  of  pliocene  hills  which  are  raised 
from  1000  to  3000  feet  above  the  level  of  the  sea.  The  rocks 
are  entirely  composed  of  limestones,  marls,  sandstones,  and  vol- 
canic products.  These  hills  are  separated  from  ^Etna  by  the  low 
plain  of  Catanea. 

The  strata  consists  of  three  groups,  and  are  represented  in 
Fig.  58. 

Fig.  58. 


3  2 

SECTION    NEAR    SYRACUSE    (SICILY). 


(1.)  TJie  Great  Limestone  Formation.  —  This  is  of  a  yellowish 
white  or  pure  white  color,  and  has  the  appearance  of  a  rock  pre- 
cipitated from  the  waters  of  mineral  springs,  being  arranged  in 
thick  beds,  often  without  distinct  lines  of  stratification.  It  attains 
a  thickness  of  800  feet,  abounds  in  caverns,  and  contains  shells, 


t  example  of  the  pliocene  in  England  ?     Where  are  the  best  examplei 
found  ?     Of  what  does  the  Val  di  Noto  consist  ? 


168  TERTIARY    PERIOD. 

most  of  which  are  identical  with  those  now  inhabiting  the  Med 
iterranean  Sea.     From  this  fact  it  is  inferred  that  it  is  the  last 
or  most  recent  of  the  pliocene  deposits. 

(2.)  Calcareous  Sandstones,  Conglomerates,  and  Schistose  L'tme- 
stones,  several  hundred  feet  in  thickness,  constitute  the  next  group 
in  the  descending  order,  and  these  repose  upon, 

(3.)  Blue  and  White  Marls,  under  which  are  blue  and  white 
days  without  fossils. 

The  limestones  and  marls  are  filled  with  the  remains  of  shell 
fish,  of  which  a  large  proportion  are  recent  species. 

At  the  southeiTi  base  of  ^Etna,  near  La  Motte,  there  are  altern- 
ate beds  of  clay,  sand,  and  volcanic  matter,  together  with  con- 
glomerates and  columnar  basalt. 

The  most  important  deposits  in  Sicily  consist  of  marls  (3), 
which  are  of  great  thickness,  and  differ  from  each  other  but 
slightly  in  color  and  mineral  composition.  The  lower  beds  are 
much  contorted,  and  contain  sulphur,  salt,  and  gypsum  in  great 
abundance ;  but  only  a  few  organic  remains,  as  the  skeletons  of 
fLl-es. 

Upon  the  marls  limestones  were  deposited  (2),  and  upon  these 
blue  marls  ;  then  sands,  sandy  limestones,  and,  finally,  the  great 
limestone  beds  (1),  which  are  found  to  cap  hills  in  some  places 
3000  feet  in  height. 

It  is  obvious  that  this  entire  series  must  have  been  deposited 
beneath  salt  water.  The  island,  therefore,  must  have  formed  the 
bed  of  the  sea,  into  which  the  materials  were  brought  from  the 
neighboring  continent  by  fluviatile  and  volcanic  agencies,  and 
very  gradually  deposited,  for  we  find  the  strata  throughout  filled 
with  the  remains  of  marine  mollusca. 

Several  long  periods  of  time  are  requisite  to  account  for  the 
deposition  of  sedimentary  and  volcanic  rocks  to  the  depth  of  3000 
feet,  for  it  should  be  observed  that  not  a  single  shell-fish  could 
be  imbedded  after  the  island  emerged  above  the  surface  of  the 
waters.  It  was  not,  then,  till  after  the  last  sediment  was  thrown 
down  that  the  island  was  raised  to  its  present  position. 

Describe  the  several  deposits  in  Sicily.  What  is  the  evidence  that  theso 
deposits  require  long  periods  of  time  ? 


EUROPEAN    PLIOCENE.  169 

When  we  consider  the  magnitude  of  the  changes  wrought  dur- 
ing this,  the  most  recent  portion  of  the  pliocene  period,  the  whole 
formation  of  ^Etna  is  truly  insignificant,  for  nearly  the  whole 
mountain  has  been  built  up  to  its  present  height  of  11,000  feet, 
and  90  miles  in  circumference,  since  the  deposition  and  elevation 
of  these,  the  last  of  the  pliocene  strata. 

3.  Sub-Apcnnine  Tertiary  Beds. — During  the  same  period  sim- 
ilar deposits  were  in  progress  on  the  western  side  of  the  Apen- 
nines in  Italy.     The  rocks  here  consist  of  brown  and  blue  marls, 
overlaid  and  interstratified  with  thick  beds  of  sandstone  and  vol- 
canic products.     The  strata  are  filled  throughout  with  marine 
shells,  which  are  sometimes  associated  with  beds  of  lignite  and 
fresh- water  shells.     The  marls  attain  a  vertical  thickness  of  2000 
feet.     The  sandy  beds  pass  into  conglomerates,  and  give  clear 
indications  of  river  action  during  their  deposition. 

Similar  strata  are  also  found  on  the  eastern  side  of  the  Apen- 
nines, and  extend  to  the  Morea,  and  to  the  islands  still  further 
east.  Deposits  of  this  period  occur  also  in  Spain,  near  Olot,  so 
that  a  large  portion  of  Southern  Europe  was  submerged  beneath 
the  Mediterranean  Sea  during  the  pliocene  period. 

4.  Brown  Coal  Formation. — Perhaps  the  most  remarkable  of 
the  pliocene  strata  occur  in  the  valley  of  the  Rhine,  between 
Coblentz  and  Cologne.     They  consist  mostly  of  lignite  or  brown 
coal,  and  contain  the  largest  quantity  of  vegetable  matter  which 
has  been  formed  since  the  carboniferous  period.     The  coal  rests 
upon  loose  silicious  sand,  which  sometimes  hardens  into  sand- 
stone, and  sometimes  into  conglomerate,  through  which  are  dis- 
tributed thin  leaves  of  lignite  calledpaper  coal,  and  silicified  wood 
often  passing  into  chalcedony  or  semi-opal.     Beds  of  clay  often 
succeed  these  silicious  deposits,  and  form  the  stratum  on  which 
the  lignites  or  principal  mass  of  the  coal  rests.     Some  portions 
of  the  lignite  consist  of  solid  wood,  of  a  black  color,  and  so  per- 
fectly preserved  as  to  be  used  for  timber,  while  other  portions  are 
mineralized  by  carbonate  of  iron,  or  replaced  by  coarse  quartz- 
ose  sand.     Associated  with  the  lignites,  and  especially  with  the 

Describe  the  sub-Apeanine  beds ;  the  brown-coal  formation. 

H 


170  TERTIARY    PERIOD. 

paper  coal,  are  some  very  remarkable  fossils,  rather  imperfectly 
preserved ;  they  consist  mostly  of  insects,  mollusca,  fishes,  ba- 
trachians,  and  quadrupeds. 

5.  Lacustrine  Deposit  of  the  Rhine. — There  is  another  interest- 
ing lacustrine  deposit,  where  the  Rhine  issues  from  Lake  Con- 
stance, consisting  of  highly  fossiliferous  marls  and  limestones. 

The  lower  beds  are  cream-colored  marls,  filled  with  the  remains 
of  plants,  fishes,  and  fresh-water  molluscs. 

Highly  fossiliferous  beds  of  fetid  marlstone  and  limestone  sue 
ceed,  in  which  have  been  found  the  skeleton  of  a  fox,  allied  to  ex- 
isting species ;  also  fishes  of  large  size,  a  tortoise  three  feet  in 
length,  crustaceans,  and  insects. 

The  strata  are  horizontal,  and  are  raised  several  hundred  feet 
above  the  Rhine.  It  is  evident,  therefore,  that  changes  in  the 
relative  level  of  sea  and  land,  similar  to  those  in  the  south,  must 
have  taken  place  in  this  part  of  Europe,  although  the  deposits 
were  made  mostly  in  lakes. 

III.  Fossils  of  the  Pliocene.  1.  Vegetables. — The  remains  of 
vegetables  are  found  in  most  of  the  pliocene  deposits :  the  most 
remarkable  of  which  is  the  brown  coal  formation  already  de- 
scribed. Trees  in  a  very  perfect  state  of  preservation  abound, 
while  the  paper  coal  is  mostly  made  up  of  the  leaves  of  the  pop- 
lar, birch,  and  the  same  species  of  plants  generally  that  are  found 
in  the  existing  forests. 

2.  Animals. — (1.)  The  remains  of  the  lower  orders  of  animals 
are  frequently  met  with,  but  they  do  not  differ  from  existing  spe- 
cies sufficiently  to  require  any  description. 

(2.)  Mollusca. — The  stratum  of  marl  in  South  Carolina,  which 
is  referred  to  this  period  by  Professor  Tuomey,  is  very  rich  in 
fossils,  consisting  mostly  of  the  remains  of  mollusca. 

The  following  table  exhibits  the  proportion  of  recent  to  extinct 
species  in  South  Carolina  : 

Describe  the  lacustrine  deposits  of  the  Rhine.  What  is  said  of  the  fossi] 
vegetables  1  of  the  animals  ?  of  the  mollusca  ? 


FOSSILS    OP   THE    PLIOCENE.  171 

No.  of  Species.  Species  Recent  Per  Cent. 

Brachiopoda 1 0 0 

Gasteropoda 78 39 50 

Lamellibranchiata 109 47 43 

Cirripedia 2 1 50 

Total 190 "87 46 

The  proportion  of  recent  species  is  probably  somewhat  larger, 
and  this  fact  would  place  these  deposits  with  the  Crag  of  England, 
which  belongs  to  the  older  pliocene  of  Mr.  Lyell. 

In  Europe  the  remains  of  shell-fish  are  the  most  abundant  fos- 
sils, of  which  more  than  800  species  have  been  already  described. 
They  are  very  similar  to  existing  species. 

(3.)  Articulata. — The  remains  of  lobsters,  insects,  &c.,  are  not 
very  abundant.  The  most  noted  locality  of  fossil  insects  is  at 
CEningen,  near  Lake  Constance,  where  many  species,  in  the  dif- 
ferent states  of  larva,  pupa,  and  imago,  have  been  very  perfectly 
preserved  in  a  stratum  of  marl.  They  appear  to  have  fallen  into 
the  lake  from  the  flowers  upon  its  bank,  and  to  have  become  en- 
veloped by  the  fine  marly  sediment. 

(4.)  Fishes. — The  tertiary  deposits  have  yielded  more  than  350 
species  of  fossil  fishes,  but  the  most  interesting  of  them  are  found 
in  the  miocene  and  eocene. 

The  most  celebrated  locality  belonging  to  the  pliocene  is  at 
CEningen.  The  genera  are  chiefly  allied  to  the  modern  carp  and 
tench,  with  an  extinct  species  of  pike.  Although  the  number  of 
individuals  is  large,  not  more  than  20  species  have  been  described. 
The  tertiary  marls  in  South  Carolina  contain  several  species  of 
fish,  particularly  of  those  belonging  to  the  shark  family. 

(5,)  Reptiles. — The  remains  of  batrachians,  frogs,  toads,  and 
newts  are  found  in  the  marl  beds  of  the  Rhine,  at  CEningen,  as- 
sociated with  a  gigantic  salamander  three  feet  in  length,  whioti 
was  at  first  described  as  a  "fossil  man  /" 

Frogs  and  other  reptiles  are  also  abundant  in  the  brown  coal, 
The  following,  Fig.  59,  represents  one  species  of  frog : 

What  is  said  of  the  articulata  ?  of  fishes  ?  Where  is  the  most  celebrated  lo 
cality  ?  Mention  the  reptiles  of  the  pliocene. 


RANA   DILUVIANA.      (BEOWN  COAL.) 

(6.)  Mammalia. — The  molars  and  tusks  of  the  mastodon  max- 
imus,  and  the  horns  of  an  extinct  species  of  deer,  have  been  found 
in  South  Carolina. 

The  remains  of  species  of  elephant,  rhinoceros,  hippopotamus, 
horse,  ox,  deer,  and  mastodon  occur  in  several  European  local- 
ities, most  of  them  in  the  English  Crag. 

The  teeth  of  a  porcupine  occur  in  the  pliocene  of  Tuscany. 
The  remains  of  the  bear,  hyena,  fox,  and  wolf  at  GEningen.  A 
water  mole,  as  large  as  a  hedge-hog,  on  the  coast  of  Norfolk, 
and  a  monkey  and  bat  occur  in  the  pliocene  of  Suffolk,  England. 
The  types  of  organization  in  all  these  extinct  animals  are  very 
similar  to  those  of  their  existing  representatives,  but  some  of  the 
species  are  of  a  much  larger  size. 

SECTION  II.— MIOCENE  OR  MIDDLE  TERTIARY. 

Immediately  beneath  the  deposits  described  in  the  last  section 
we  find  a  group  of  strata  of  great  extent,  somewhat  similar  in 
composition  and  structure,  but  characterized  by  different  fossils, 
called  the  Miocene  or  Middle  Tertiary. 

I.  Miocene  of  the  United  States. — The  miocene  strata  occur  at 
different  points  skirting  the  Atlantic  sea-board,  from  Massachu- 
setts to  the  Gulf  of  Mexico.  Mr.  Conrad,  from  the  small  number 
of  extinct  species  of  shells,  has  referred  the  deposits  ofYorktown, 

Mention  the  mammalia.     Describe  the  miocene  of  the  United  States. 


MIOCENE   OP   THE    UNITED    STATES.  173 

Smithfield,  and  Suffolk,  in  Virginia ;  those  of  Easton  and  St. 
Mary's,  in  Maryland,  and  of  Cumberland  City,  New  Jersey,  to 
the  older  pliocene  of  Mr.  Lyell ;  but  as  we  have  already  noticed 
the  fact  of  there  being  but  two  principal  divisions  of  the  tertiary 
in  the  United  States,  the  lowest  group  undoubtedly  belongs  to 
the  eocene ;  and  as  the  other  strata  were  deposited  immediately 
upon  it,  we  have  concluded  to  class  them  with  the  miocene,  al- 
though from  the  character  of  the  fossils  there  would  seem  to 
have  been  a  long  period  intervening  between  the  close  of  the 
eocene  and  commencement  of  the  miocene  period. 

1.  Gayhead. — A  good  example  of  miocene  clays  occurs  at 
Gayhead,  Martha's  Vineyard,  a  section  of  which  is  represented 
in  the  following  diagram  (Fig.  60),  A  B  : 

Fig.  60. 


c  c 

SECTION    AT    GAYHEAD,    MASS. 


The  strata  consist  of  variously-colored  clays,  inclined  at  a  high 
angle,  and  dipping  toward  the  northeast.  They  contain  beds 
of  lignite  (c  c),  sharks'  teeth,  and  other  fossils. 

The  strata  are  of  great  vertical  thickness,  amounting  to  several 
hundred  feet,  and  their  great  inclination  indicates  considerable 
disturbance  in  this  part  of  New  England  since  their  deposition. 

2.  But  the  principal  deposits  of  this  period  are  found  in  Mary 
land,  Virginia,  and  the  more  southern  states. 

The  miocene  of  Virginia  comprehends  all  the  area  extending 
from  the  sea-board  to  Northbury,  on  the  Pamunkey  River,  and 
to  Coggin's  Point,  on  the  James  River.  The  western  limit  is  a 
wavy  line  passing  nearly  north  and  south  through  these  places. 

In  the  eastern  portions  the  surface  is  level,  and  elevated  not 
more  than  6  or  8  feet  above  the  tide.  The  western  part  attains 
an  elevation  of  from  30  to  80  feet.  These  higher  regions  are 
separated  from  the  lower  by  a  terrace,  which  gives  the  highest 
evidence  of  having  been  the  shore  of  the  sea.  The  surface  is 

Give  examples.    Where  are  the  principal  deposits  found  f 


174  TERTIARY   PERIOD. 

generally  level,  but  is  cut  through  by  innumerable  ravines,  and 
intersected  by  creeks,  which  open  into  the  principal  rivers. 

The  cliffs  of  York  River  present  the  following  kinds  of  rocks  : 

(1.)  The  lower  stratum  is  a  bluish  sandy  clay,  containing  great 
numbers  of  Turritella  alticosta  and  Sytherea  Sayana. 

(2.)  To  this  succeeds  a  layer  of  brownish  yellow  sand,  with  but 
few  shells. 

(3.)  The  next  stratum  consists  mostly  of  Crepidula  costata,  so 
closely  packed  together  that  very  little  sand  or  clay  can  gain  ad- 
mission. 

(4.)  The  whole  is  overlaid  with  strata  of  coarse  highly  ferru- 
ginous sand. 

In  approaching  Yorktown  the  character  of  the  cliff  changes, 
and  attains  a  higher  elevation.  The  lower  stratum  exchanges  its 
turritella  for  crepidula,  and  disappears.  Different  shells  also  ap- 
pear in  the  other  groups. 

Higher  up  the  river  the  shelly  bed  becomes  changed,  being 
composed  almost  entirely  of  comminuted  shells,  so  cemented  as 
to  form  a  porous  rock  40  feet  in  height,  which  thins  out  toward 
the  west.  The  fragmentary  character  of  this  rock,  and  the  in- 
clination of  the  shelly  fragments,  although  the  beds  are  horizon- 
tal, clearly  indicate  the  action  of  the  surf  and  of  tidal  currents. 
In  some  places  a  band  of  iron  ore  overlies  the  fossiliferous  strata. 

The  most  important  fact  connected  with  these  and  other  mio- 
cene  strata  is  the  existence  of  marl  beds,  composed  of  carbonate 
of  lime,  and  containing  particles  of  green  sand,  a  silicate  of  iron, 
which  render  them  highly  fertilizing  manures. 

Similar  miocene  deposits  exist  on  the  James  River,  and  the 
region  south  of  it ;  between  the  Potomac  and  Rappahannock ;  in 
Maryland,  New  Jersey,  and  North  and  South  Carolina. 

A  cliff  on  the  north  bank  of  the  James  River  presents  the  fol 
lowing  kinds  of  rock,  which  will  illustrate  the  fossiliferous  char- 
acter of  these  strata  (Fig.  61). 

1.  Six  feet  of  sand  and  clay  overlying  the  shelly  strata. 

2.  One  foot  of  reddish  clay. 

What  kind  of  rocks  do  the  cliffs  of  York  River  present  ?  What  is  the  most 
important  fact  connected  with  the  miocene  strata?  Describe  the  miocene  of 
James  River. 


MIOCENE    OF   THE    UNITED    STATES.  175 

3.-  A  band  of  small  pebbles  Fig. 

only  a  few  inches  in  thickness. 

4.  A  layer  of  sand  3  feet  thick, 
containing  Ckama  and  Venus  de- 
formis. 

5.  A  stratum  4  feet  thick,  con- 
sisting mostly  of  a  compact  mass 
of  Ckama  and  Area  centenaria. 

6.  A  stratum  2  feet  thick,  most- 
ly of  large  Pectens. 

7.  Another  stratum  of  Ckama, 

with  Area  centenaria,  Panopea  rcjlexa,  about  6  feet  in  depth. 

8.  A  second  layer  of  Pectens,  with  Ostrea  compressirostra,  1  foot 
thick. 

9.  Another  layer  of  CJiama  3  feet  thick. 

10.  A  layer  of  Pectens  and  Ostrea  5  feet  in  thickness. 

The  marl  stratum  is  very  extensive  ;  it  is  found  on  both  shores 
of  the  Chesapeake  Bay,  100  miles  from  north  to  south,  and  50 
miles  wide.  In  Virginia,  and  North  and  South  Carolina,  the 
marl  strata  are  of  equal  and  perhaps  still  greater  extent. 

3.  General  Description  of  the  Miocene  of  the  United  States. — 
Without  attempting  to  describe  the  strata  in  the  several  localities, 
it  may  serve,  perhaps,  to  give  a  better  view  of  our  miocene  beds 
to  arrange  them  in  a  section.  It  is  proper  to  observe,  however, 
that  the  whole  series  is  not  found  at  any  one  point,  and  that  the 
subdivisions,  as  in  the  preceding  section  on  James  River,  are 
often  more  numerous  than  are  represented  in  the  following  figure. 
Those  who  would  obtain  a  more  minute  and  extensive  knowledge 
of  our  tertiaries,  will  find  ample  materials  in  the  Geological  Re- 
ports of  the  several  states. 

It  will  be  observed  that  the  miocene  properly  consists  of  three 
groups :  the  blue  marls,  the  yellow  and  gray  marls,  and  sands 
and  clays. 

1.  The  Blue  Marls. — This  group  is  composed  chiefly  of  a  fine 
blue  clay  of  a  dark  color,  and  of  a  soapy  feel  when  wet,  but  of  a 
oluish  gray  when  dry. 

Give  a  general  description  of  the  miocene  of  the  United  States.  Into  how 
many  and  what  kinds  of  rock  may  the  miocene  of  the  United  States  be  divid- 
ed? Describe  the  blue  marls. 


176 


fERTIARY    PERIOD. 
mg.  62. 


SECTION    OF    THE    MIOCENE    OF   THE    UNITED    STATES    OF   AMERICA. 

1.  The  first  and  lowest  bed,  Fig.  62  (1),  is  a  thin  stratum  of  pebbles,  sep- 


arating the  miocene  from  the  eocene,  E. 


tng 
.  Lo 


wer  blue  marl. 


3.  Upper  blue  marl. 


4.  Lower  portion  of  the  yellow  marl.    5.  Upper  portion  of  the  yellow  marl. 

6.  Horizontal  beds  of  sand  and  clay  partially,  and  in  some  cases  wholly  re- 
moved by  aqueous  agency. 

7.  Pleistocene  sand  and  clay. 

The  lower  beds  are  more  sandy,  and  contain  shells  in  a  very 
perfect  state  of  preservation,  associated  with  fragments  of  zoo- 
phytes, resembling  corals. 

The  upper  portions  are  characterized  by  a  beautiful  little 
bivalve  shell,  the  Mactra  Modicella,  in  such  numbers  as  to  con- 
stitute in  most  cases  one  half  the  weight  of  the  rock.  These 
shells  are  also  found  in  the  lower  beds,  and  in  the  marls  above, 
but  not  to  the  exclusion  of  other  species. 

The  perfection  of  the  shells,  and  their  association  in  groups, 
prove  that  they  lived  and  died  on  the  spot,  and  hence  these  strata 
were  deposited  in  quiet  water  and  in  a  very  gradual  manner. 

2.  The  Yellow  and  Gray  Marls  are  a  series  of  beds  reposing 
upon  the  preceding,  of  a  yellowish  or  grayish  yellow  color,  and 
composed  in  part  of  a  very  gritty  sand.  The  lower  and  more 
eastern  beds  are  clayey  in  their  texture,  and  of  a  dark  brownish 
yellow,  a  color  produced  by  the  presence  of  oxide  of  iron.  In 
the  western  portion  of  these  beds  they  are  of  a  lighter  color,  and 
attain  a  thickness  of  from  15  to  25  feet. 

Describe  the  yellow  and  gray  marls. 


EUROPEAN    MIOCENE.  177 

In  the  upper  beds  the  fossils  are  not  so  perfectly  preserved , 
they  appear  to  have  been  worn  by  the  action  of  water  to  a  kind 
of  sand,  and  then  firmly  cemented  by  the  infiltration  of  carbonate 
of  lime,  forming  a  tertiary  limestone.  This  limestone,  when  first 
taken  out  of  the  bed,  is  soft,  but,  on  exposure  to  the  air,  rapidly 
hardens  into  a  durable  compact  rock.  The  layers  or  fragments 
are  laid  upon  each  other  at  every  inclination,  although  the  strata 
are  as  a  whole  horizontal,  plainly  showing  an  agitated  state  of 
the  waters  during  their  deposition. 

3.  Horizontal  strata  of  Sand  and  Clay  overlie  the  marls ;  the 
lower  beds  appear  to  have  been  quietly  and  slowly  deposited, 
and  as  the  whole  group  is  destitute  of  marine  shells,  and  con- 
tains pieces  of  wood,  it  was  probably  deposited  from  the  over' 
Sowings  of  the  streams,  after  the  manner  of  the  deltas  of  existing 
rivers.  The  above  description  of  the  miocene  applies  particu- 
larly to  Virginia  and  Maryland. 

These  marls  contain  on  an  average  40  per  cent,  of  carbonate 
of  lime.  In  South  Carolina  the  proportion  amounts  to  70  per 
cent.  The  lime,  and  the  grains  of  green  sand  which  are  distrib- 
uted through  most  of  the  marls,  render  them  an  excellent  dress- 
ing for  the  land. 

When  we  consider  that  in  Virginia  alone  the  marl  stratum 
covers  an  area  of  from  200  to  300  square  miles,' furnishing  inex- 
haustible sources  of  fertility  to  the  soil,  we  can  form  some  esti 
mate  of  its  great  value  to  agriculture. 

II.  European  Miocene. — 1.  The  lower  portion  of  the  Crag  for 
mation  is  the  only  representative  of  this  period  in  the  British 
Isles. 

It  consists  of  the  coralline  and  the  red  crag.  The  former  ex- 
tends over  an  area  of  80  square  miles,  and  is  about  20  feet  thick ; 
the  latter  exceeds  40  feet  in  vertical  depth.  This  group  is  dis- 
tinguished for  the  great  number  of  corals  which  are  associate** 
with  its  mineral  contents. 

In  many  parts  of  Europe  the  miocene  strata  are  of  great  thick- 
ness, and  cover  extensive  areas.  Deposits  of  this  period  are 

What  is  said  of  the  marl  stratum  ?    What  example  of  miocene  in  Bngland  1 

H2 


178  TERTIARY    PERIOD. 

found  in  the  west  of  France,  the  great  valley  of  Switzerland,  the 
basins  of  Vienna  and  Styria,  extending  to  the  plains  of  Hungary; 
in  portions  of  Poland  and  Southern  Russia,  and  in  the  northern 
parts  of  Italy. 

2.  Basin  of  the  Garonne. — From  the  mouth  of  the  Garonne  to- 
ward the  southeast  there  exists  a  series  of  miocene  strata,  con- 
sisting of  quartzose  sand  mixed  with  marls.  The  marls  contain 
great  numbers  of  fluviatile  shells,  associated  with  others  of  marine 
origin.  These  fossiliferous  beds  are  separated  from  the  chalk  by 
strata  of  fresh- water  limestone. 

In  this  part  of  France  the  miocene  rocks  may  be  divided  into 
four  groups :  1.  The  first  and  highest  member  of  the  series  con- 
sists of  silicious  sands  destitute  of  shells.  2.  The  second  group 
is  mostly  gravel.  3.  The  third  is  composed  of  sand  and  marl, 
with  shells.  4.  And  the  fourth  of  blue  marl,  which  is  also  filled 
with  shells. 

The  fresh-water  limestone  near  Bordeaux  shows  that  the  sur 
face  must  have  been  alternately  occupied  by  fresh  and  salt  water, 
and  hence  there  must  have  been  elevations  and  depressions  of 
the  land  during  the  formation  of  these  rocks. 

Fig.  63. 


1  2 

SECTION   OF   THE    VALLEY    OF    SWITZERLAND. 

3.  Valley  of  Switzerland. — Between  the  Alps  and  the  Jura,  in 
the  valley  of  Switzerland,  of  which  Fig.  63  is  a  section,  are  found 
extensive  deposits  of  miocene  strata.     Between  the  Lakes  Ge 
neva  and  Lucerne,  the  strata  consist  of  three  kinds  of  rock. 

(1)  The  first  is  a  coarse  conglomerate,  which  gradually  passes 
into 

(2)  A.  fine  sandstone  called  Molasse.     This  sandstone  is  very 
thick  and  rather  soft,  although  some  of  it  is  suitable  for  building 
materials. 

(3)  Various  bands  of  marl  and  lignite,  evidently  of  fresh-water 

Describe  the  miocene  deposits  in  the  basin  of  the  Garonne ;  in  the  valley  of 
Switzerland. 


MIOCENE    OF   THE    VALLEY    OP    SWITZERLAND.  179 

origin,  as  they  contain  the  remains  of  fresh- water  shells,  are  dis- 
tributed through  the  molasse.  The  whole  reposes  on  secondary 
limestone  (4). 

The  conglomerate  and  sandstone  are  at  this  point  destitute  of 
fossils ;  but  further  to  the  north,  marine  shells  and  other  organic 
relics  occur,  from  which  it  has  been  inferred  that  the  deposits  of 
this  basin  were  made  in  an  estuary  opening  into  the  sea  toward 
the  northeast. 

The  molasse  forms  hiils  300  feet  in  height  above  the  Lake  of 
Geneva;  the  whole  must,  therefore,  have  been  elevated  with  a 
large  portion  of  the  Alps  since  these  strata  were  deposited. 

In  the  valleys  of  the  Jura  and  the  Rhine  similar  beds  are  found 
containing  fresh-water  shells.  In  some  parts  of  Rhenish  Bavaria, 
the  strata  of  sand  and  marl  contain  fossils  which  show  a  transition 
from  the  older  or  eocene  deposits. 

The  most  important  examples  of  the  miocene  strata,  however, 
are  to  be  found  in  the  central  and  eastern  portions  of  the  conti- 
nent. 

4.  Miocene  Basins  of  Vienna  and  Styria. — The  strata  of  these 
basins  consist  of  conglomerates,  sandstones,  and  marls,  overlaid 
by  coralline  limestone  of  great  thickness,  cotemporaneous  with 
the  red  and  coralline  crag  of  Suffolk,  England. 

Fig.  64.  , 

/i, 


3  1 

SECTION   OF   THE   BASIN  OF   VIENNA. 


In  the  basin  of  Vienna,  of  which  Fig.  64  is  a  section,  we  find, 
First  (1),  gravel;   secondly  (2),  fresli-water  limestone  ;   and 
thirdly  (3),  a  kind  of  marl  called  Leitha  kalk.     The  whole  re- 
poses on  (4)  Alpine  limestone,  which  is  a  secondary  rock. 

In  the  basin  of  Styria,  the  upper  beds  alternate  with  volcanic 
ashes  ejected  from  the  extinct  craters  on  the  borders  of  Hunga- 
ry. The  coralline  limestone,  which  is  mostly  covered  near  Vi- 
enna by  calcareous  marls,  has  here  a  vertical  thickness  of  400 

Where  are  the  most  important  examples  found  ?  of  what  do  the  basins  of 
Vienna  and  Styria  consist? 


180  TERTIARY    PERIOD. 

foet.  Each  group  is  filled  with  the  remains  of  mammalia  and 
shell-fish. 

Numerous  other  beds  of  this  period  are  found  in  other  parts 
of  Europe  and  in  Asia;  our  limits,  however,  will  allow  of  but 
one  more  example. 

5.  Miocene  Beds  of  Auvergne. — In  the  center  of  France,  in  the 
district  of  Auvergne,  the  miocene  deposits  are  noted  for  the  char- 
acter of  their  fossils,  and  for  containing  beds  of  alluvium  and  vol- 
canic rocks. 

The  following  section,  Fig.  65,  exhibits  the  order  of  the  strata 
at  Mont  Perrier.  They  repose  upon  the  eocene  lacustrine  strata. 

Fig.  65.  (1)  Newer  alluvium ;  (2) 

Miocene  alluvium,  contain- 
ing bones ;  (3)  Breccia,  con- 
2,  „  sisting   mostly  of  volcanic 

products ;  (4)  Miocene  allu- 
vium, filled  also  with  the 

SECTION    AT    MONT    PERRIER,  AUVERGNE.        bones     Qf    many    gpeciCS    of 

quadrupeds ;  (t)  Tr  achy  tic  breccia  and  (I)  compact  basalt. 

In  the  two  beds  of  alluvium  not  less  than  40  species  of  extinct 
mammalia  have  been  discovered,  many  of  which  are  peculiar  to 
this  locality. 

By  inspecting  this  section,  and  studying  the  character  of  the 
materials  and  of  the  imbedded  fossils,  it  is  easy  to  trace  the  order 
and  succession  of  changes  during  the  formation  of  these  strata. 

1.  First,  then,  after  the  eocene  strata  (e)  had  been  deposited 
and  covered  with  lava  (Z),  they  were  elevated  and  subjected  to 
the  action  of  water,  which  wore  off  their  edges  and  formed  a  basin. 

2.  Into  this  basin  the  materials  of  the  alluvium  (4),  with  the 
quadrupeds  then  inhabiting  the  land,  were  conveyed. 

3.  Then  succeeded  eruptions  from  the  neighboring  volcanoes 
throwing  out  pumice  and  ashes,  and  melting  the  snows  upon 
their  flanks,  by  means  of  which  great  floods  of  water  accumulated 
in  the  gorges,  bearing  along  the  ejected  materials  with  angular 
fragments  of  trachyte,  and  depositing  the  mass  upon  the  alluvi- 
um, forming  the  trachytic  breccia  (3). 

Describe  the  miocene  beds  of  Auvergne. 


FOSSILS    OF    THE    MIOCENE.  18l 

4.  Upon  this  another  bed  of  alluvium  (2),  during  a  period  of 
repose,  was  deposited,  with  the  remains  of  similar  animals. 

5.  Finally,  another  series  of  volcanic  eruptions  took  place,  by 
which  the  breccia  (t)  were  spread  over  the  whole  group. 

That  volcanic  eruptions  were  frequent  during  the  eocene  and 
miocene  periods  in  this  part  of  France,  we  have  the  most  con 
vincing  proofs,  in  the  existence  of  more  than  60  extinct  craters, 
some  of  which  are  represented  in  the  accompanying  figure,  so 
perfectly  preserved  that  the  lava  streams  can  be  traced  to  a  great 
distance,  as  distinctly  as  those  of  ^Etna  or  of  Vesuvius. 

Fig.  66. 


EXTINCT    VOLCANOES    OF   AUVERGNE. 


III.  Fossils  of  ike  Miocene. — The  miocene  deposits  contain  a 
larger  number  of  extinct  species  than  the  pliocene. 

1.  Vegetables. —  The  remains  of  vegetables  are  abundant  in 
many  localities.     In  some  cases  beds  of  lignite  are  interstratified 
with  the  miocene  clays,  as  at  Gayhead,  Massachusetts. 

In  the  miocene  strata  of  Richmond,  Virginia,  pieces  of  drift- 
wood have  been  discovered,  perforated  by  canals  similar  to  those 
made  by  the  Teredo.  When  these  fragments  of  wood  are  dried, 
they  constitute  a  true  lignite.  Some  hickory  fruits  exist  in  a  fos 
sil  state  in  the  same  locality. 

In  Europe,  similar  vegetable  remains  are  found  in  most  of  the 
miocene  beds.  The  vegetables,  however,  were  very  generally 
allied  to  existing  species. 

2.  Animals. — (1.)  The  shells  of  infusorial  or  microscopic  ani- 
mals constitute  strata  of  considerable  thickness.     A  stratum  of 
white  clay,  from  12  to  20  feet  thick,  at  Richmond,  Virginia,  con- 

What  proof  of  volcanic  agency  during  this  period  ?  What  is  said  of  the 
fossil  vegetables  ?  What  remains  of  animals  are  there  at  Richmond,  Virginia ! 


182  TERTIARY    PERIOD. 

sists  mostly  of  the  silicious  skeletons  of  several  species  of  N 
ula,  Gaillonella,  Actinocyclus,  and  Coscinodiscus,  Figs.  67  and  68. 


Fig.  67. 


Navicula.  

Gaillonella 

Actinocyclus. 

The  same  stratum  of  marl,  containing  some  new  fossil  formst 
is  also  found  at  Petersburg,  so  that  it  probably  extends  over  a 
large  area.  A  similar  stratum  occurs  at  Tampa  Bay,  Florida ;  the 
bed  appears  to  be  interposed  between  the  eocene  and  miocene. 

The  polishing  slate  of  Bilin  (Germany)  forms  a  series  of  strata, 
14  feet  in  thickness,  entirely  made  up  of  the  silicious  shells  of 
gaillonellse,  so  extremely  small  "  that  a  cubic  inch  of  stone  con- 
tains  forty '-one  thousand  millions  /'* 

Professor  Bailey,  who  has  examined  these  minute  animals,  has 
observed  two  species  of  living  gaillonellae,  from  Melville  Island, 
identical  with  the  fossils  of  the  Richmond  marl ;  hence  the  north- 
ern seas  contain  minute  animals,  whose  species  extend  back  over 
vast  periods,  to  a  time  when  they  had  a  much  wider  distribution 
than  at  present. 

The  lower  classes  of  animals,  the  Radiata,  Infusoria,  &c.,  are 
frequently  found  associated  with  innumerable  generations  of 

(2.)  Mollusca,  the  remains  of  which,  both  fresh-water  and  ma- 
rine, are  not  only  distributed  through  most  of  the  miocene  beds, 
but  often  constitute  the  principal  portion  of  their  substance.  This 
is  the  case  with  the  miocene  marls  of  Eastern  Virginia  and  Ma- 
ryland. Many  of  the  shells  are  nearly  as  perfect  as  their  living 
representatives.  The  casts  of  Chama  are  cemented  into  a  hard 
compact  rock,  and  each  bed  is  characterized  by  the  preponder- 
ance of  one  or  more  species.  The  shells  are  found  associated  in 
colonies,  which  proves  that  the  animals  lived  and  died  on  the  spot 
where  their  remains  are  found.  The  prevailing  genera  are  Cha- 

Of  what  does  the  polishing  slate  of  Bilin  consist  ?  What  discovery  was  made 
by  Prof.  Bailey  ?  What  fossil  shells  are  found  in  the  United  States  ? 


FOSSILS    OF    THE    MIOCENE.  183 

ma,  Area,  Pecten,  Ostrea,  Venus,  Crassatella,  Crepidula,  Pectun- 
culus,  and  Isocardia. 

In  the  miocene  deposits  of  Europe  the  same  general  types  are 
found,  although  the  species  are  for  the  most  part  distinct,  and  each 
locality  is  characterized  by  different  shells.  The  characteristic 
shells  in  the  basin  of  the  Garonne  belong  to  the  genera  Cardita, 
Concellaria,  Pyrula,  and  Vaginula.  The  whole  number  of  fossil 
species  in  the  various  miocene  rocks  of  Europe  amount  to  more 
than  1000,  of  which  about  one  fourth  are  extinct. 

(3.)  The  remains  of  Articulata,  such  as  crabs,  lobsters,  and  in- 
sects, are  not  very  abundant,  but 

(4.)  Fishes,  particularly  of  the  shark  family,  flourished  in  great 
numbers,  both  in  Europe  and  America,  during  this  and  the  pre- 
ceding period. 

The  tooth  of  a  shark  found  at  Gayhead  is  much  larger  than  that 
of  any  living  species  :  the  animal  to  which  it  belonged  must  have 
been  70  feet  in  length.  A  tooth  found  in  North  Carolina  is  still 
larger,  measuring  5  inches  in  height  and  41  in  width  :  the  largest 
in  the  collection  of  Professor  Gibbes,  of  South  Carolina,  is  6£ 
inches  in  height,  and  5  inches  across  the  extremities  of  the  root. 
Fig.  69,  on  the  following  page,  is  one  of  the  teeth  of  the  Car- 
charodon  megalodon,  the  largest  species  of  this  genus.  These 
animals,  if  we  may  judge  from  the  size  of  their  teeth,  must  have 
been  100  feet  in  length.  Other  teeth  are  represented  among 
the  eocehe  fossils,  page  199.  The  teeth  are  rarely  altered  in 
composition  ;  the  serratures  of  their  edges,  and  their  entire  struc- 
ture, are  as  perfect  in  most  cases  as  those  of  existing  sharks.  The 
great  abundance  of  the  teeth  which  have  been  found  does  not 
necessarily  prove  that  these  animals  were  more  numerous  than 
some  other  families  of  fishes,  for  the  teeth  of  sharks  are  arranged 
in  several  rows,  and  are  very  durable,  so  that  a  single  individual 
would  furnish  a  large  number.  But,  from  the  greater  number  cf 
species,  it  is  obvious  that  they  attained  a  much  larger  develop- 
ment, and  prevailed  in  greater  numbers  than  at  the  present  time. 

Describe  the  fossil  shells  of  Europe.  What  are  the  principal  remains  of 
fishes  ?  Give  examples. 


134 


TERTIARY    PERIOD. 
Jig.  69. 


CARCHARODON    MEGALODON. 


(5.)  Reptiles,  such  as  batrachians  and  tor- 
toises, are  frequently  met  with  in  the  lignites, 
although  their  remains  are  not  so  abundant  in 
any  of  the  tertiary  rocks  as  in  those  of  the  sec- 
ondary periods.  Fig.  70  represents  a  tooth  of 
a  reptile,  evidently  a  species  of  crocodile. 
Some  of  the  teeth  of  another  reptile  allied  to 
the  crocodile  were  found  in  company  with  the 
preceding,  but  the  exact  locality  is  not  given. 


These  remains  probably  belong  to  the  miocene 

ia. — See 
ber,  1850,  p.  233. 


nj.  70. 


long  tc 

of  Virginia. — See  Journal  of  Science,  Septem- 
'  r,  1850,  p.  233. 

(6.)  Birds. — In  Auvergne  and  in  Ascension 

What  is  said  of  the  reptiles  of  the  miocene  1  of  the  birds  ? 


FOSSILS    OF    THE    MIOCENE. 


185 


Island,  a  few  vertebrae  and  the  eggs  of  birds  have  been  dis- 
covered, but  their  remains  are  quite  rare  in  the  miocene  rocks, 
although  this  fact  does  not  prove  any  deficiency  of  the  feathered 
tribes  during  this  period.  See  page  102. 

(7.)  Mammalia  are  abundant  in  several  of  the  miocene  de- 
posits. 

The  most  characteristic  mammal  of  this  period  was  found  in 
the  valley  of  the  Rhine,  near  Eppelsheim,  and  is  called  the  Di- 
notherium,  Fig.  71. 

Fig.  71. 


DINOTHERIUM. 


From  certain  fragments  of  the  teeth  and  head  the  animal  has 
been  restored.  It  was  18  feet  in  length,  and  resembled  in  its 
proportions  the  American  tapir.  It  had  two  tusks  in  the  lower 
jaw,  similar  to  those  in  the  upper  jaw  of  the  walrus.  Fitted  by 
its  structure  and  magnitude  for  living  mostly  in  water,  this  ani- 
mal appears  to  have  formed  a  connecting  link  between  the  aquat- 
ic mammalia  and  the  land  pachydermata.  Associated  with  these 
remains  were  those  of  thirty  extinct  species  of  fossil  mammalia. 

In  the  miocene  alluvions  of  Auvergne,  more  than  forty  species 
have  been  described.  The  large  pachydermata  are  very  abund- 
ant, as  species  of  elephant,  mastodon,  hippopotamus,  rhinoceros, 
tapir,  bear,  and  horse. 

There  are  also  the  bones  of  many  other  families,  as  of  the  ox 
tribe,  many  species  of  deer,  three  species  of  the  cat  family  (Felis), 
and  three  species  of  bears.  This  locality  has  also  furnished  the 
remains  of  a  species  of  dog,  otter,  beaver,  hare,  water-rat,  glut- 
Describe  the  most  characteristic  mammal.  What  other  mammals  ? 


136 


TERTIARY    PERIOD. 


ton,  and  of  a  peculiar  genus,  the  agnotherium,  which  was  allied 
to  the  dog,  but  as  large  as  a  lion. 

The  tooth  and  other  remains  of  a  seal  were  discovered  by  Dr. 
Burton  in  the  miocene  of  Richmond,  and  have  been  described 
by  Dr.  Wyman  in  Silliman's  Journal  for  September,  1850.  Also 
the  tooth  of  the  Phocodon  (Agassiz),  Fig.  72,  an  animal  allied  to 
the  basilosaurus  of  Harlan.  See  page  203. 

In  the  same  deposits  Dr.  Burton  discovered  the  remains  of  a 
Cetacean,  allied  to  the  whale,  a  portion  of  the  jaw  of  which  is 
represented  in  Fig.  73,  a. 

Fig.  72. 


The  seas  of  the  pliocene  and  miocene  periods  were  filled  with 
marine  mammalia,  such  as  species  of  walrus,  whale,  dolphin,  seal, 
and  lamartin ;  but  every  species  of  mammalia,  and  even  some  of 
the  genera  which  flourished  at  the  time,  and  whose  remains  are 
distributed  through  many  beds  of  rock,  have  long  since  ceased 
to  have  any  living  representatives. 

They  were  created  and  adapted  to  the  conditions  under  which 
they  were  to  live ;  they  enjoyed  their  brief  period  of  existence, 
and  having  left  in  the  rocks  the  imperishable  memorials  of  life 
and  death,  have  been  succeeded  by  other  forms  suited  in  turn 
to  the  altered  conditions  of  the  earth's  surface. 


What  remains  of  cetaceans  have  been  discovered  ? 
representatives  ?     What  reason  is  assigned  for  this  ? 


Have  they  any  living 


EOCENE  OP  THE  UNITED  STATES. 


187 


SECTION  EL— EOCENE  OR  OLDER  TERTIARY. 

The  strata  embraced  in  the  eocene  division  of  the  tertiary  are 
better  defined,  and  more  extensive  and  important,  than  either  of 
the  preceding  groups. 

I.  Geographical  Distribution. — In  the  United  States  eocene 
deposits  underlie  the  miocene,  extending  from  Maryland  through 
Virginia,  North  and  South  Carolina,  Georgia,  and  the  states  bor- 
deiing  the  Gulf  of  Mexico. 

In  South  America  there  are  two  extensive  deposits,  called  the 
Patagonian  and  Guaranian. 

Cotemporaneous  strata  are  spread  over  the  southeast  of  En- 
gland, occupying  the  London  and  Hampshire  basins,  the  Paris 
basin,  and  district  of  Auvergne  in  Central  France,  the  basin  of 
the  Netherlands,  Aix  in  Provence,  the  southern  flanks  of  the  Alps, 
the  eastern  portion  of  the  Grecian  Archipelago,  and  the  sub 
Himalayan  range  of  mountains  in  Northern  India.  Of  these  ex- 
tensive deposits  we  can  present  but  a  few  examples. 

II.  Eocene  of  the  United  States. — In  South  Carolina  there  are 
three  principal  groups. 

1.  The  Buhr-stone  Group. — This  is  mostly  composed  of  sand, 
clay,  marl,  silicified  shells,  and  bands  of  iron  ore.  The  following 
section,  Fig.  74,  from  Aiken  to  Horse  Creek,  exhibits  the  order 
and  character  of  this  group  : 


Fig.  74. 


G.  Granite. 

1.  Beds  of  sandstone  and 
grit. 

2,  3.  Beds  of  sand,  gravel, 
colored  clays,  &c. 

4.  Silicious  clay  bed. 

5.  Silicified  shells. 

6.  Beds  of  sand  and  iron 
ore. 


SECTION  AT  AIKEN,  s.  c. 


This  section  embraces  a 
vertical  depth  of  200  feet,  and  the  rocks  belong  to  the  lower  di- 
vision of  the  eocene. 


How  are  the  eocene  deposits  distributed?     Describe  the  fcahi-stone  group* 
What  is  said  of  the  section  at  Aiken,  S.  C.  ? 


188  TERTIARY    PERIOD. 

The  most  important  stratum  is  that  containing  the  silicified 
shells,  marked  5  in  the  section.  It  is  about  30  feet  thick.  The 
shells  have  left  their  hollow  casts,  which  are  filled  with  silica, 
giving  a  porous  structure  to  the  rock,  on  which  account  it  is  ad- 
mirably fitted  for  millstones.  Porcelain  clay,  of  a  superior  qual- 
ity, is  foand  in  the  beds  below,  the  lower  part  of  which  exhibits 
marks  of  considerable  disturbance  during  its  deposition.  Asso- 
ciated with  the  clays  are  pieces  of  silicified  wood,  shells,  and 
bones  of  extinct  animals. 

2.  Santee  Beds. — The  Charleston  basin  is  about  75  miles  long, 
and  60  miles  wide.     The  eocene  beds  here  consist  of  white 
limestone,  marls,  and  green  sand.     The  strata  are  highly  calca- 
reous, and  the  marls  are  in  some  places  hard,  and  in  others  clay- 
ey.    This  group  also  occupies  the  lower  portion  of  the  eocene. 

3.  Eocene  of  the  Ashley  and  Cooper  Rivers. — The  eocene  beds 
on  these  rivers  occupy  a  higher  position,  and,  in  connection  with 
the  Santee  beds,  are  600  or  700  feet  in  thickness.    They  are  com- 
posed of  various  marls,  and  are  noted  for  the  remains  of  sharks, 
chelonians,  cetaceans,  and  quadrupeds. 

The  following  section  shows  the  relative  position  of  the  eocene 
rocks  in  South  Carolina. 

Fig.  75. 


12  3  4 

SECTION    OF    THE    EOCENE    OF    SOUTH    CAROLINA. 

1.  Ashley  and  Cooper  beds.  4.  Buhr-stone  formation. 

2.  Coralline  marl.  5.  Pleistocene. 

3.  Santee  beds. 

4.  The  Eocene  of  the  James's  River •,  Virginia,  consists  also  of 
clays  and  sands  of  a  greenish  tinge.  They  often  contain  green 
sand,  gypsum,  shells,  &c.,  and  repose  upon  sandstone.  The  lat- 
ter is  much  channeled,  showing  the  long  action  of  aqueous  cur- 
rents previous  to  the  eocene  period.  Similar  beds  occur  on  the 
Potomac. 

Which  is  the  most  important  stratum  ?  Describe  the  Santee  beds  ;  the  eo> 
cene  of  the  Ashley  and  Cooper  Rivers ;  of  James  River. 


EUROPEAN    EOCENE. 


189 


D,  Eocene  deposits  are  found  in  all  the  states  bordering^the 
Gulf  of  Mexico.  The  most  celebrated  localities  are  at  Tampa 
Bay  in  Florida,  Claiborne  in  Alabama,  Vicksburg  in  Mississippi, 
and  Washita  River  in  Louisiana. 

6.  The  following  table  will  give  a  chronological  view  of  the 
ei>cene  of  tho  United  States,  with  the  characteristic  fossils : 


IhTisions. 

Localities. 

Characteristic  Fossils. 

Upper 
or 
N^wer  Eocene. 

Vicksburg,  Miss.,  white  limestone  of 
St.  Stephen's,  and  of  Claiborne, 
Al.,  and  part  of  that  of  the  Charles- 
ton basin,  S.  C. 

Limestone  in  the  vicinity  of  Tampa 
Bay,  Florida. 

IScutella  Lyelli. 
"        Rogersi. 
Pecten  Poulsoni. 
Nummulites  Mantelli. 

{Nummulites  Flo  rid  ana. 
Crestellaria  rotella. 
Ostrea  Georgiana. 

Lower 
or 
C*!der  F?ocene. 

Fossiliferous  sands  of  Claiborne  and 
St.  Stephen's,  Al.  ;  of  the  Washita 
River,  near  Monroe,  La.  ;  Pamun- 
key  River  at  Marlbourne,  and  eo- 
cene green  sand  on  James's  River, 
below  City  Point,  Va.  ;  Fort  Wash- 
ington, Piscataway,  and  Upper 
Marlborough,  Md. 

Cardita  planicosta. 
"       Blandingi. 
.Crassatella  alta. 
Ostrea  sellseformis. 
Turritella  Mortoni. 

Conrad. 

III.  European  Eocene. — The  most  important  tertiary  deposits 
in  Europe,  as  well  as  in  America,  were  formed  during  the  older 
fN  eocene  period. 

In  England  the  eocene  is  chiefly  found  in  basin-shaped  de- 

Fig.  7fi. 


1.  Marine  sand. 
4.  Chalk. 


2.   London  clay. 
5.  Green  sand. 


3.  Plastic  clay. 
6.  River  Thames. 


1.  Marine  or  Bagshot  sand,  400  feet  thick. 

2.  London  clay,  350    " 

3.  Mottled  clays  and  sand,  or  plastic  clay,  85  feet  thick. 


What  is  said  of  the  European  eocene  ? 
of  the  Thames  ?     Describe  them. 


What  kinds  of  rock  in  the  basin 


190  TERTIARY    PERIOD, 

pressions  of  the  chalk.     There  are  three  principal  basins — the 
basin  of  the  Thames,  of  Hampshire,  and  of  the  Isle  of  Wight. 

1.  Basin  of  the  Thames. — The  deposits  here  consist  mostly  of 
what  is  called  the  London  clay.  The  strata  are  divided  into  three 
groups,  and  are  represented  in  the  preceding  section,  Fig.  76. 

(1.)  The  beds  of  the  lower  division,  which  form  the  base  of 
the  London  clay,  rest  on  the  chalk,  and  often  contain  rolled  frag- 
ments of  chalk  and  flint.  The  deep  indentations  in  the  chalk, 
and  the  irregularity  of  the  surface,  give  striking  evidence  that  it 
was  subjected  to  the  action  of  water  for  a  long  time  previous  to 
the  commencement  of  the  eocene  period.  In  the  lower  beds, 
fresh-water  shells,  drift-wood,  and  various  species  of  plants  have 
been  discovered,  but  the  great  mass  consists  of 

(2.)  London  clay,  which  varies  from  300  to  600  feet  in  thick- 
ness. It  is  of  a  blackish  color,  tough,  and  often  mixed  with  a 
greenish  earth,  white  sand,  and  flattened  masses  of  clayey  lime 
stone,  called  "  septaria."  The  latter  contain  cracks  filled  with 
calcareous  spar,  and  are  used  for  Parker's  cement. 

At  the  mouth  of  the  Thames,  on  the  Isle  of  Sheppey,  cliffs  are 
exposed  more  than  200  feet  in  height,  and  the  total  thickness  of 
the  clay  is  not  less  than  600  feet.  This  locality  has  been  long 
celebrated  for  its  fossils.  More  than  50  species  of  fishes,  a  num- 
ber of  crustaceans,  and  other  invertebrate  animals,  bones  of  large 
serpents  and  of  birds  of  prey,  are  found;  but  the  most  interesting 
are  the  fossil  fruits,  berries,  and  woody  seed-vessels  of  several 
hundred  species  of  plants.  These  fossils  are  strongly  impreg- 
nated with  iron  pyrites,  which  renders  them  very  brittle  and  per 
ishable. 

The  character  of  the  vegetable  remains  indicates  a  tropical 
climate,  and  the  existence  of  numerous  spice  islands  in  the  vicin- 
ity during  the  deposition  of  these  strata. 

(3.)  The  Bagshot  sands  are  mostly  silicious,  but  sometimes 
marly,  and  are  nearly  destitute  of  organic  remains.  These  strata 
are  found  capping  the  Highgate  and  the  Hampstead  Hills,  near 
London,  and  were  no  doubt  formerly  continuous  over  the  whole 

What  is  said  of  the  London  clay  ?  of  the  Bagsbot  sands  ? 


EOCENE. PARIS    BASIN.  191 

surface,  but  have  been  mostly  carried  away  by  the  subsequent 
agency  of  water. 

2.  In  the  Hampshire  Basin  the  strata  are  much  thicker,  and 
vary  somewhat  in  composition.     The  following  table  by  Mr. 
Prestwich  exhibits  the  order  and  average  thickness  of  the  sev- 
eral groups : 

(1.)  Fluvio-marine  and  fresh-water  series  .  350  feet. 

(2.)  Barton  clays 300     " 

(3.)  Bracklesham  sands 700     " 

(4.)  Bangor  beds 250     " 

(5.)  Mottled  clay  and  sand 150     " 

Total 1750 

The  first  three  groups  lie  above  the  London  clay,  and  the  others 
are  cotemporary  with  it.  In  the  upper  groups  of  this  basin  and 
in  the  Isle  of  Wight,  beds  of  fresh-water  origin  alternate  with 
those  deposited  in  salt  water.  It  is  evident,  therefore,  that  the 
deposits  were  made  in  an  estuary  opening  into  the  sea. 

3.  Paris  Basin. — The  eocene  basin,  upon  which  the  city  of 
Paris  is  built,  is  about  100  miles  from  east  to  west,  and  180  miles 
from  northeast  to  southwest.     The  total  thickness  is  700  feet. 

The  following  section  of  the  Paris  basin,  Fig.  77,  will  serve 
to  exhibit  the  order  of  the  several  groups  of  strata: 

Fig.  77. 


SECTION    ON    THE    BANK    OF    THE    SEINE PARIS    BASIN. 

6.  Upper  fresh-water  sands.  7.  Upper  marine  sands. 


4.  Gypsum.  5.  Green  marls. 

2.  Calcaire  grassier.  3.  Calcaire  siliceux. 

1.  Plastic  clay.  c.  Chalk. 

(I.)  Plastic  Clay. — The  lowest  and  oldest  stratum  is  of  fresh- 
water origin,  and  reposes  upon  the  chalk  (c).     It  is  composed  of 

What  is  the  depth  and  character  of  the  deposits  in  the  Ha  mpshire  basin  I 
What  is  the  extent  of  the  Paris  basin  ?     Describe  the  plastic  clay. 


192  TERTIARY    PERIOD. 

clay  and  lignite,  and  contains  rolled  pebbles  of  chalk  and  of  flint, 
associated  with  fresh-water  shells.  The  portion  of  clay  called 
"plastic  clay"  is  extensively  employed  in  pottery,  and  some  of 
it  is  used  for  the  finest  porcelain  ware. 

(2.)  Calcaire  Grassier. — This  stratum  is  a  marine  limestone,  oc- 
cupies the  northern  part  of  the  Paris  basin,  and  is  remarkable 
for  the  great  numbers  of  fossil  shells.  More  than  400  species 
have  been  obtained  from  a  single  locality  at  Grignon,  near  Paris. 
The  shells  are  imbedded  in  a  sand  composed  chiefly  of  fragments 
of  shells.  Nearly  140  species  of  the  genus  Cerithium  have  been 
described.  There  are  also  strata  of  argillaceous  and  calcareous 
marls,  alternating  with  limestones,  some  of  which,  in  the  lower 
beds,  are  Nummulitic.  (See  page  197.) 

(3.)  Calcaire  Siliceux. — The  next  stratum  is  a  silicious  lime 
stone,  a  fresh- water  formation,  apparently  deposited  from  mineral 
springs.     It  is  almost  destitute  of  organic  remains ;  but  its  struc- 
ture is  peculiar,  being  filled  with  small  empty  cavities,  on  which 
account  some  of  it  is  employed  for  millstones  (BuJir-stone). 

(4  &  5.)  Gypseous  Series. — A  series  of  white  and  green  marls, 
containing  gypsum,  and  also  limestone,  reposes  upon  the  calcaire 
grossier,  and  constitutes  a  remarkable  group  of  fresh-water  ori- 
gin. The  celebrated  plaster  of  Paris  quarries  are  found  in  this 
group,  and  in  the  center  of  the  basin. 

The  gypsum  is  supposed  to  have  been  chemically  precipitated 
from  the  waters  of  the  southern  rivers.  How  the  water  became 
impregnated  with  such  large  quantities  of  this  mineral  is  not  cer- 
tainly known  ;  but  it  was  probably  due  to  volcanic  agency,  which 
we  know  was  active  about  this  period  in  Auvergne,  near  the 
sources  of  the  rivers.  Fluviatile  shells,  wood,  the  bones  of  fresh- 
water fish,  reptiles,  birds,  and  quadrupeds,  are  abundant.  From 
these  strata  Cuvier  derived  the  materials,  bones  of  mammalia, 
which  formed  the  basis  of  his  great  discoveries,  and  laid  the  foun* 
dation  of  the  science  of  Palaeontology. 

(6.)  Upper  Marine  Sands. — The  next  group  consists  of  marls, 
micaceous  and  quartzose  sands,  and  beds  of  sandstone  filled  with 

Describe  the  calcaire  grossier;  the  calcaire  siliceux;  the  gypseous  series. 
What  important  fact  connected  with  these  beds?  What  other  groups  in  this 


EOCENE  BASINS  OF  AUVERGNE. 


193 


marine  shells.  These  beds  are  separated  from  the  gypsum  by  a 
thin  bed  of  oyster  shells,  and  are  generally  situated  upon  the 
summits  of  the  hills. 

(7.)  Upper  Fresh-water  Sands. — The  highest  and  last  group 
of  this  basin  consists  of  fresh-water  marls,  which  are  interstrali- 
fied  with  layers  of  flint,  and  contain  numerous  animal  and  veg- 
etable remains,  especially  the  seed-vessels  of  aquatic  plants 
These  deposits  appear  to  have  been  formed  in  marshes  and  fresh- 
water lakes  after  the  basin  had  been  nearly  filled,  and  portions 
of  it  elevated  above  the  water. 

The  alternations  of  marine  and  fresh-water  deposits  in  the 
Paris  basin  indicate  several  elevations  and  depressions  of  the 
land  during  this  period,  and  yet  a  few  of  these  groups  may  have 
been  cotemporaneous,  for  some  of  the  marine  strata  were  de- 
posited in  that  part  which  was  open  to  the  sea,  while  the  fresh- 
-  78-  water  deposits  were  thrown 

down  near  the  mouths  of  rivers. 
We  have  then,  in  this  part  of 
France,  an  ancient  gulf  of  the 
chalk,  opening  into  the  sea  to- 
ward the  northeast.  Into  this 
gulf  large  rivers  from  the  south 
emptied,  bearing  along  the  land 
animals,  plants,  and  fresh-water 
shells,  which  inhabited  the  land 
and  the  water  at  the  time.  By 
a  series  of  elevations  and  depres- 
sions, the  sea  was  alternately  ad- 
mitted and  driven  out,  until  the 
whole  basin  was  filled  and  ele- 
vated to  its  present  position,  a 
monument  of  the  agencies  of  life 
and  death  during  inconceivable 
periods  of  the  past. 

4.  Eocene  Basins  ofAuvergne. 
— In  the  center  of  France  there 

Give  a  summary  of  the  changes.  Describe  the  eocene  basins  ofAuvergne, 
Cantal,  and  Velay. 

I 


194  TERTIARY    PERIOD. 

are  three  lacustrine  deposits  of  the  tertiary,  represented  in  tho 
map  on  the  preceding  page,  Fig.  78,  Auvergne,  Cantal,  and  Ve- 
lay.  The  strata  consist  of  nearly  horizontal  beds  of  sandstone, 
marls,  clays,  and  limestones,  which  are  all  of  fresh- water  origin, 
and  repose  on  granitic  rocks. 

The  most  northern  is  in  the  valley  of  the  Allier,  and  is  devel- 
oped on  each  side  of  that  river  for  a  considerable  distance,  with 
an  average  width  of  20  miles. 

The  rocks  consist  of  four  groups. 

(1.)  Sandstones  and  Conglomerates  abound  upon  the  borders 
of  the  basin.  The  band,  however,  is  not  continuous  around  the 
entire  margin,  but  interrupted  at  different  points,  apparently  by 
torrents  from  the  neighboring  high  lands.  The  beds  contain  an- 
gular and  rounded  fragments  of  the  primary  rocks  of  the  region, 
granite,  gneiss,  mica,  and  clay-slates.  Lignite  and  pieces  of  wood 
are  found,  but  no  shells. 

(2.)  Red  Marl  and  Sandstone,  somewhat  resembling  the  red 
sandstones  of  an  older  period,  abound  in  some  parts  of  the  basin. 

(3.)  Green  and  Wliite  foliated  Marls  next  occur  near  the  cen- 
ter of  the  basin,  composed  of  the  same  materials,  but  of  very  fine 
texture.  The  marls  are  not  less  than  seventy  feet  in  thickness, 
and  thinly  foliated.  This  structure  arises  from  thin  scales  of  the 
Cypris,  a  genus  of  small  crustaceous  animals,  species  of  which 
now  inhabit  stagnant  pools,  and  annually  cast  off  their  crustaceous 
envelopes. 

These  yearly  deposits  have  given  rise  to  divisions  in  the  marl, 
BO  that  the  leaves  are  as  thin  as  paper,  and  what  most  astonishes 
us  is  the  fact  that  this  structure  extends  through  several  hundred 
feet  of  vertical  depth,  indicating  a  clear  and  tranquil  state  of  the 
water,  and  pointing  to  the  immense  periods  of  time  during  which 
the  beds  were  forming. 

The  three  groups  were  probably  in  the  process  of  formation 
at  the  same  time ;  for  while  the  marls  were  thrown  down  in  the 
center  of  the  basin,  the  coarser  materials  would  be  deposited 
near  the  margin,  and  be  formed  into  conglomerates  and  sand- 
tones. 

(4.)  Limestone,  Travertine,  Oolite. — The  preceding  rocks  fre- 
quently pass  into  limestones,  which  in  some  cases  are  oolitic,  that 
is,  are  composed  of  concretions  which  resemble  small  eggs.  Some 

Of  how  many  groups  do  the  rocks  consist  in  the  valley  of  the  Allier?  Do 
scribe  them 


FOSSILS    OF    THE    EOCENE.  195 

of  the  limestones  are  filled  with  the  cases  or  indusice  of  the  larvae 
of  Phryganeae,  and  are  called  indusial  limestones. 

The  larvae  of  this  family  are  accustomed  to  attach  to  their  dwell- 
ings small  shells,  grains  of  coarse  sand,  &c.  The  extinct  species 
of  the  same  genus  had  similar  habits.  The  tubes  were  thus  left, 
when  the  animal  had  passed  through  its  metamorphosis,  on  the 
bottom,  to  be  covered  with  mud,  and  to  give  character  to  the 
strata.  (See  page  198.) 

(5.)  Gypseous  Marls. — On  the  right  of  the  Allier  there  are 
strata  more  than  50  feet  thick  of  laminated  gypseous  marls  simi- 
lar to  those  in  the  Paris  basin.  These  beds  rest  on  strata  of  green 
cypriferous  marls,  alternating  with  grits.  The  whole  constitutes 
a  stratum  whose  vertical  depth  is  more  than  250  feet. 

In  Velay  and  Cantal  the  fresh-water  formations  are  similar  to 
those  in  Auvergne,  although  in  Cantal  the  deposits  are  more  sili- 
cious,  contain  flints,  and  can  hardly  be  distinguished  from  the 
chalk. 

5.  Nummulitic  Formation  of  the  Alps. — Some  of  the  higher 
Alps  are  formed  of  nummulitic  limestones,  with  overlying  strata 
of  dark  slates.  This  group  was  formerly  supposed  to  belong  to 
a  much  older  period,  but  lately  it  has  been  referred  to  the  older 
eocene,  many  of  the  fossils  being  identical  with  those  of  the 
Paris  basin ;  hence  it  is  inferred  that  the  upheaval  of  the  Alps, 
with  all  the  contortions  and  dislocations  of  the  strata,  have  occur- 
red since  the  deposition  of  a  considerable  portion  of  the  eocene  ; 
and  that  while  the  London  clay  was  in  the  process  of  accumula- 
tion, the  ocean  still  rolled  its  waves  over  the  space  now  occupied 
by  some  of  the  highest  summits  of  the  Alps. — Lyell. 

IV.  Fossils  of  the  Eocene. — At  the  commencement  of  the  eo- 
cene period,  types  of  animals  and  vegetables,  closely  resembling 
those  which  now  exist,  were  brought  upon  the  earth's  surface ; 
we  should  expect,  therefore,  that  these  fossils  would  be  similar 
to  those  already  described.  In  general  this  is  the  fact,  but  there 
are  some  which  are  characteristic  of  this  period,  and  some  which 
are  common  also  to  the  miocene. 

Of  what  are  some  of  the  higher  Alps  composed  ?  What  reason  for  placing 
them  in  the  eocene  ?  What  types  of  animals  and  vegetables  were  introduced 
with  the  eocene  ? 


196 


TERTIARY    PERIOD. 


1.  Vegetables. — In  the  eocene  deposits  of  the  United  States 
and  Europe,  the  remains  of  vegetables  often  form  beds  of  lignite, 
in  which  the  leaves  and  portions  of  the  wood  of  trees  are  found 
in  abundance  ;  particularly  is  this  the  case  in  fresh-water  basins  ; 
but  the  vegetable  remains  which  have  excited  most  attention  are 
those  of  the  London  clay  (Isle  of  Sheppey).  Several  hundred 
species  have  already  been  determined,  all  extinct,  yet  indicating 
by  their  structure  the  tropical  character  of  the  climate  at  the  time 
they  flourished. 

The  remains  of  the  seeds  and  seed-vessels  give  to  these  fossils 
a  peculiar  interest.  The  following  figures  represent  some  of  tha 
most  common  of  their  fruits  : 


1.  Pterophiloides  Richardsoni, 

2.  Nipadites  cordiformis,  $. 

3.  Cucurraites  variabilis,  fr.* 


4.  Wetherellia  variabilis,  $.* 

5.  Faboidea  semicurvilinearis,  $.* 


The  most  abundant  of  these  fruits  are  those  called  "fossil  jigs" 
(2).  They  are  allied  to  the  fruits  of  the  Pandanus  or  screw  pine, 
and  also  to  the  Nipa.  The  latter  is  a  small  tree  growing  in 
marshy  and  clayey  places  in  the  Indian  Archipelago.  From  this 
resemblance  the  fossil  fruits  are  called  Nipadites.  Thirteen  spe- 
cies have  been  described  by  Mr.  Bowerbank. 

Some  of  these  fruits  have  a  striking  resemblance  to  coffee  (4). 
Others  are  referable  to  the  cucumber  and  gourd  family  (3). 
Others,  still,  resemble  the  common  scarlet  bean  (5),  with  some  pe- 
culiarities which  distinguish  them  from  any  living  plant.  There 
have  been  at  least  35  species  of  this  latter  genus  found  at  Shep- 
*  Fractional  parts  of  natural  size. 


The  most  remarkable  locality  of  fossil  vegetables  ?    What  is  their  character  1 
Describe  the  fossil  fruits  of  the  Isle  of  Sheppey. 


FOSSILS    OF    THE    EOCENE.  197 

pey.  There  are  two  bean-like  fruits,  the  one  allied  to  the  A  ra- 
tio,, and  the  other  to  the  common  Laburnum. 

Mr.  Bowerbank  has  found  other  fruits  allied  to  the  pepper,  the 
cardamom,  the  cotton-plant,  the  cypress,  and  the  coniferae  (1). 

Most  of  these  families  are  now  represented  by  the  existing 
tropical  plants,  although  all  the  species  and  at  least  one  genus 
have  long  since  passed  from  the  surface  of  the  earth. 

2.  Animals. — (1.)  The  lower  and  microscopic  animals  wore 
very  abundant  during  the  eocene  period,  although  they  do  not 
appear  to  have  formed  as  extensive  beds  of  rock  as  were  depos- 
ited during  the  miocene  period ;  but  a  family  of  very  minute  an- 
imals, allied  both  to  shell-fish  and  polyps,  called  Foraminifera, 
have  contributed  to  the  formation  of  extensive  strata,  not  only  in 
the  tertiary,  but  in  the  older  rocks. 

Some  of  the  shells  of  these  animals  are  microscopic,  and  others 
are  of  the  size  of  a  small  coin,  and  are  called  Nummulites.  Fig. 
79  represents  several  forms. 

Fig.  79. 


GROUP   OF   FORAMINIFERA. 

a.  Lineolaria.  /.   Operculina. 

b.  Nummulites.  g.  Polymorphina. 

c.  Frondiculina.  h.  Frondiculina. 

d.  Vincularia.  i.    Triloculina. 
c.  Marginulina.  j.  Alveolina. 

Nummulites  are  the  largest  and  most  widely  diffused;  theii 
shell  is  divided  into  a  vast  number  of  chambers,  which  communi 
cate  with  each  other.  Many  of  the  eocene  rocks  are  little  else 
than  aggregations  of  these  shells.  Several  thick  beds  of  the  cal- 

What  is  said  of  the  lower  forms  of  animals  during  this  period  ?     What  fam- 
ily is  the  largest  and  most  widely  diffused  ? 


198  TERTIARY   PERIOD. 

caire  grassier  are  entirely  composed  of  a  small  species  called  the 
Miliola,  from  its  resemblance  to  millet-seed. 

(2.)  The  London  clay  contains  some  corals,  but  they  are  gen- 
erally of  small  size.  Corals  and  sponges  have  been  observed  in 
all  the  eocene  deposits  of  the  United  States.  The  species  indi- 
cate a  shallow  sea  in  which  the  animals  lived. 

(3.)  17ie  Mollusca  of  the  eocene  present  us  with  many  species 
which  are  not  found  in  the  other  divisions  of  the  tertiary. 

Many  of  the  strata  are  made  up  of  comminuted  shells. 

The  buhr-stone  of  the  United  States  appears  to  have  been  com 
posed  at  first  of  shells,  but  their  places  have  become  supplied 
with  silex,  although  the  form  of  the  shell  is  still  retained. 

The  European  eocene  is  characterized  by  similar  shells,  al 
though  the  species  differ,  and  some  3  or  4  in  100  are  identical 
with  those  which  now  inhabit  the  adjacent  seas. 

(4.)  The  Remains  of  Crustaceans. — Lobsters,  crabs,  &c.,  abound 
in  the  Isle  of  Sheppey,  at  which  place  more  than  thirty  species 
have  been  discovered. 

A  very  small  crustacean,  Cypris  (Fig.  80  is  a  living  species  of 
this  genus),  contributed  largely  to  the  formation  of  the  fresh- water 
marls  in  Auvergne  (see  p.  194).  With  the  marls  are  associated 
limestones,  formed  by  an  aggregation  of  the  indusice  of  the  Caddis- 
worm  (May-fly).  These  are  little  tubes  coated  with  small  shells, 
and  bits  of  wood  or  straw,  and  remain  after  the  larva  have  passed 
into  the  perfect  state.  Fig.  81  represents  one  of  these  tubes, 

Fig.  80.  Fig.  81. 


CYPRIS.  CADDIS-WORM. 

(5.)  Fishes* — The  remains  of  fishes  are  abundant  throughout 

*  The  uumber  of  species  of  fossil  fishes  determined  by  M.  Agassiz  amounts 
to  1500. 

What  is  said  of  the  mollusca  of  the  United  States  ?  of  Europe  ?     Describe 
the  Crustacea;  the  fishes. 


FOSSILS    OF    THE    EOCENE. 


199 


the  eocene  rocks.  The  most  interesting  are  those  of  the  squalidae 
or  shark  family.  In  the  miocene  and  eocene  of  the  United  States 
the  teeth  of  several  genera,  and  of  a  great  number  of  species,  have 
been  described  by  Professor  R.  W.  Gibbes,  of  South  Carolina. 
From  his  monograph  of  this  family  we  select  the  following  ex 
amples,  Fig.  82. 

Fig.  82. 


For  Carcharodon  megalodon,  see  page  184. 

1.  Galeocerdo  aduncus.  5.  Sphyrna  prisca. 

2.  "  minor.  6.  Notidanus  primigenius. 

3.  Hemipristis  serra.  7.  Lanma  elegans. 

4.  Glyphis  subulata.  8.  Otodus  obliquus. 

9.  Oxyrhina  hastalis. 

Classification  of  Fishes. — M.  Agassiz  has  divided  fishes  into  four  ordera, 
founded  upon  the  peculiar  structure  of  the  scales. 

I.  Placoid  (broad  plate}. — The  skin  in  this  order  is  covered  with  enameled 
plates,  as  in  the  shark  family.  Fig.  83,  No.  1,  represents  a  plate,  and  No.  2  the 
prickly  tubercles  of  ray  fishes. 

What  fishes  most  pi'evailed  ?  What  evidence  of  this  ?  What  division  has 
been  made  of  the  fishes  ?  What  is  the  basis  of  the  classification  ? 


200 


TERTIARY    PERIOD. 

Fig.  83. 


II.  Ganoid  (splendid}. — The  scales  are  composed  of  piates  of  bone  or  horn, 
covered  with  a  thick  layer  of  enamel,  identical  in  structure  with  the  teeth, 
No.  3.     The  sturgeon  belongs  to  this  order. 

III.  Ctenoid  (toothed  or  comb-like'). — The  scales  are  formed  of  plates,  which 
are  toothed  like  a  comb,  Nos.  4  and  5.     The  perch  is  an  example  of  this  family 

IV.  Cycloid  (circular). — In  this  order  the  scales  are  plates  of  bone  or  horn, 
without  enamel,  No.  6.     The  borders  are  smooth,  but  the  external  surface  va« 
riously  marked.     The  mullet,  salmon,  and  carp  belong  to  this  order. 

The  fishes  belonging  to  each  of  the  orders  mentioned  above 
flourished  in  very  different  proportions  during  the  successive  ge- 
ological periods.  Those  of  the  Ganoid  and  Placoid  orders  were 
first  introduced,  and  prevailed  exclusively  till  the  cretaceous  pe- 
riod, when  the  Ctenoid  and  Cycloid  orders  were  introduced,  and 
have  continued  till  the  present  time.  They  include  five  sixths 
of  existing  species.  All  the  fossil  fishes  found  in  the  palaeozoic 
rocks  are  distinguished  by  having  the  vertebrae  of  the  tail  pro- 
longed into  one  of  the  lobes  of  the  tail,  so  that  the  lobes  are  un- 
equal, while  most  of  the  fishes  since  that  period  have  equally  bi~ 
lobate  tails.  The  tails  with  unequal  lobes  are  said  to  be  hetero- 
cercal,  and  those  with  equal  lobes  homoccrcal. 

Existing  examples  of  fishes  with  heterocercal  tails  are  sharks 
and  sturgeons. 

Coprolites. — Associated  with  the  fishes  are  their  coprolites,  or 

How  are  the  orders  distributed  through  geological  times  ?  What  are  found 
associated  with  the  remains  of  fishes  ? 


FOSSILS    OF    THE    EOCENE.  201 

foecal  remains  ;  some  of  them  are  of  large  size,  and  indicate  by 
their  structure  the  character  of  the  animals  which  existed  at  the 
time.  One  of  the  Coprolites  found  at  Richmond  was  6£  inches 
in  length,  and  3  in  diameter  The  remains  occur  in  most  of  the 
fossiliferous  rocks. 

Two  species  of  saw-fish  (Pristis)  have  been  found  in  the  Isle 
of  Sheppey,  and  one  species  at  least  in  the  United  States,  of  which 
Fig.  84  represents  a  tocth. 

Fig.  84. 


TOOTH    OF    PRISTIS    AGASSIZI. 


The  genus  Myliobatis  (Eagle  Ray),  of  which  there  are  five 
living  and  fifteen  fossil  species,  was  allied  to  the  preceding. 
Their  teeth  occur  in  the  Isle  of  Sheppey  and  in  the  eocene  of 
the  United  States. 

Fig.  85  represents  the  appearance  of  the  teeth  of  Myliobatit 
Holmesii,  from  South  Carolina. 

Fig.  85. 


MYLIOBATIS    HOLMESII. 


"  The  genus  is  characterized  by  broad,  transverse  teeth,  on  a 
flat  plate,  bounded  laterally  by  three  rows  of  narrow  hexagonal 
teeth  of  equal  length,  united  by  fine  sections.  The  arrangement 
resembles  that  of  a  tesselated  pavement." — Gibbes. 

At  the  celebrated  locality  of  Monte  Bolca,  the  remains  of  a  gi- 
gantic torpedo  was  discovered,  with  a  large  number  of  fishes  be- 
longing to  several  families. 

At  Aix,  in  Provence,  a  small  slab  of  marl  was  found  whicb 

Describe  the  fishes  found  in  South  Carolina.     Mention  other  localities, 

12 


202  TERTIARY   PERIOD. 

contains  multitudes  of  small  fishes  as  perfect  as  if  recently  im- 
bedded in  soft  mud. 

The  fishes  of  the  tertiary  period  resemble  those  that  now  ex- 
ist ;  but  all  of  the  species  and  many  entire  genera  (about  one 
third  of  those  belonging  to  the  eocene)  are  extinct. 

(6.)  Reptiles. — The  remains  of  reptiles  are  not  so  numerous  in 
the  tertiary  as  in  rocks  of  an  earlier  date,  but  the  vertebrae  of  a 
serpent  found  in  the  Isle  of  Sheppey  is  the  earliest  indication  of 
the  ophidian  tribes  on  the  surface  of  our  planet.  It  was  allied 
to  the  Boa,  and  must  have  been  20  feet  in  length.  The  croco- 
diles of  the  London  clay  were  more  nearly  related  to  those  now 
living  in  the  island  of  Borneo  than  to  those  of  the  Nile.  Tur- 
tles are  more  numerous,  and  some  of  them  attained  a  great  size. 
The  remains  of  a  turtle  found  in  the  sub-Himalayan  tertiary 
measured  twenty  feet  across  the  curve  of  the  shell.  The  fossil 
turtle  is  distinguished  from  those  that  now  exist  by  possessing  a 
combination  of  the  jaws  and  buckler  of  the  fresh  water  with  the 
bony  helmet  of  the  marine  species. 

Birds. — The  remains  of  birds  are  rare  in  the  fossil  state.  From 
the  gypseous  quarries  of  Montmartre,  near  Paris,  Cuvier  discov- 
ered nine  or  ten  species,  related  to  the  pelican,  sea-lark,  curlew, 
woodcock,  owl,  buzzard,  and  quail.  In  a  few  cases  the  skeleton 
was  nearly  entire.  The  bones  of  a  bird  allied  to  the  vulture  oc- 
cur in  the  Isle  of  Sheppey. 

Mammalia. — In  the  United  States  the  remains  of  a  remark- 
able cetacean  mammal  were  first  noticed  by  Dr.  Harlan,  of  Phil- 
adelphia, who,  in  1832,  described  a  gigantic  vertebrae,  from  the 
Washita,  weighing  44  pounds,  and  referred  it  to  a  new  genus, 
which  he  called  Basilosaurus  (king  of  Saurians). 

In  1843,  nearly  an  entire  skeleton  was  found  in  the  eocene 
limestone  of  Alabama,  and  is  now  in  the  possession  of  Dr.  J.  C. 
Warren,  of  Boston.  The  length  of  the  animal,  when  living, 
could  not  have  been  less  than  70  feet.  Dr.  R.  W.  Gibbes,  of 
Columbia,  South  Carolina,  has  described  three  species. 

What  reptiles  are  found  in  eocene  deposits  ?  Why  are  birds  rare  in  the  fos 
til  state  ?  What  remarkable  mammal  in  the  United  States  ? 


MAMMALS    OF.  THE    EOCENE. 


203 


The  following  figures  are  representations  of  the  teeth  and 
bones  of  these  remarkable  animals  : 

Fig.  86. 


Caudal  Veriebrte  of  Basilosaurus  Cetoides. 


Fragment  of  Upper  Jaw  of  Basilosaurus  Squalodon. 


Fig.  87. 


Tooth  of  Basilosaurus  Cetoides.     Nat.  size. 


The  reference  of  these 
animals  to  the  cetacean 
mammals,  or  whale  tribe, 
has  been  shown  satisfacto- 
rily, not  only  from  the  char- 
acter of  the  teeth,  and  their 
insertion  in  the  jaw  (Figs 
87  and  88),  but  from  the 
structure  of  a  cranium  dis- 
covered by  Prof.  Lewis  R. 
Gibbes,  and  described  by 
Prof.  Tuomey.  The  geo- 
logical position  of  these  re- 
mains in  South  Carolina  is 
in  the  older,  and  also  in  the 
upper  eocene  beds. 

Mr.  Koch,  a  German  collector, 
a  few  years  since  obtained  a  large 
number  of  vertebrae,  belonging  to 
many  individuals,  with  the  bones 


What  reason  for  referring  these  animals  to  the  cetacean  family  ? 


204 


TERTIARY    PERIOD. 


of  other  animals.  With  these  and  oth- 
er materials,  he  constructed  a  skeleton 
of  enormous  length,  and  exhibited  it  to 
the  public  with  the  name  of  Hydrar- 
chus.  The  imposition  was  at  first  suc« 
cessful,  until  seen  and  exposed  by  Prof. 
Wyman,  of  Boston. 

Since  these  bones  extend 
throughout  the  eocene  strata, 
these  animals  must  have  lived 
during  a  period  sufficiently  long 
for  the  deposition  of  several 
Barilosaurus  Serratus,  Gibbes.  hundred  feet  of  rock. 

The  most  characteristic  mammals  of  this  period  are  the  Pachy- 
dermata.  Four  fifths  of  the  fifty  species  of  quadrupeds  found  in 
the  Paris  basin  belong  to  one  division  of  this  order,  represented 
at  the  present  day  by  only  four  living  species,  of  which  three  are 
tapirs. 

The  two  genera,  PalcBotherium  and  Anoplotherium,  are  only 
found  in  this  early  part  of  the  tertiary  period.  The  Palceotheri- 
um,  Fig.  89,  was  intermediate  be- 
tween the  tapir  and  rhinoceros. 
Twelve  species  of  this  genus  have 
been  described,  varying  in  size  from 
that  of  the  rhinoceros  to  that  of  the 
pig.  The  animal  had  a  short  fleshy 
trunk,  and  was  adapted  to  live  in 
swampy  districts,  feeding  on  coarse 
vegetables,  like  the  tapir  of  Amer- 
ica and  Asia,  to  which  it  was  very 
nearly  allied. 

The  genus  Anoplotherium  contains  but  six  species,  varying 
much  in  size,  from  the  dimensions  of  a  pony  to  that  of  a  hare. 

Anoplotherium  Commune  is  most  abundant  in  the  Paris  basin. 
It  was  4  feet  high  and  8  feet  long,  of  which  3  feet  belonged  to 
the  tail.  It  resembled  the  otter,  and  lived  in  marshy  places. 

Anoplotherium  Gracile  was  a  much  more  graceful  and  slender: 
animal,  resembling  in  its  structure  the  gazelle.  Fig.  90. 


Palceotherium  Minor. 


During  what  period  did  these  animals  live  ?     What  is  said  of  the  pachyder- 
mata?     Describe  the  palseotherium  and  anoplotherium, 


MAMMALS    OF   THE    EOCENE.  205 

Fig.  90. 


AnoplotTierium  Gractte. 

AnoplotTierium  Leporinum,  a  much  smaller  species,  resembled 
the  hare.  The  bones  of  another  small  pachyderm,  still  more  like 
the  Jiare,  have  been  found  in  the  London  clay,  called  Hyracothe- 
rium,  and  a  very  rare  genus  called  Cheer  opt  amus,  similar  to  tho 
preceding,  in  the  Paris  basin. 

Of  the  remaining  mammals  of  the  eocene,  two  species  of  dor- 
mouse and  two  of  the  squirrel,  an  opossum,  and  a  bat,  have  also 
been  found  in  the  Paris  basin.  The  remains  of  monkeys  occur 
in  Brazil,  India,  and  in  England. 

In  the  Sewalik  Hills,  in  Northern  India,  many  remarkable  fos- 
sils have  been  discovered,  in  which  are  many  species  of  pachy- 
derrnata,  and  of  the  other  orders  of  mammals.  Of  the  pachyder- 
mata  there  are  two  species  of  mastodon,  two  new  species  of  ele- 
phant, several  new  species  of  rhinoceros  and  hippopotamus ;  sev- 
eral allied  to  the  hog;  three  new  species  of  horse,  one  of  which 
had  the  slender  and  graceful  figure  of  an  antelope. 

The  same  district  contains  the  remains  of  many  Ruminants,  as 
two  or  three  species  of  giraffe,  two  species  of  camels,  and  many 
species  of  antelopes,  deer,  oxen,  and  other  existing  genera.  But 
besides  these,  there  is  a  new  genus,  the  Sivatherittm,  a  ruminant 
larger  than  the  rhinoceros,  having  many  affinities  with  the  ele- 
phantoid  animals.  Its  head  was  large,  and  provided  with  two 
pairs  of  horns,  with  a  large  upper  lip,  probably  extended  into  a 

What  other  animals  oelong  to  the  eocene  1  What  animals  have  been  found 
in  Northern  India? 


206  TERTIARY    PERIOD. 

short  trunk,  small  eyes,  and  teeth  fitted  to  masticate  leaves  and 
twigs  rather  than  grass.  It  appears  to  have  been  intermediate 
between  the  ruminants  and  pachyderms. 

Most  of  the  other  orders  of  mammals  are  found  among  the  fos- 
sils of  this  remarkable  region. 

We  find  in  the  tertiary  rocks  all  the  orders  of  mammalia,  with 
the  exception  of  the  human  species ;  the  remains  of  man  have 
rever  been  found  in  any  but  the  most  recent  deposits,  and  hence 
the  changes  which  we  have  described  as  belonging  to  the  tertiary 
period  were  all  antecedent  to  his  existence  on  earth.* 

SECTION  IV.-CLIMATE  AND  PHYSICAL  GEOGRAPHY  OF  THE  TERTIARY. 

1.  Climate. — The  climate  of  the  United  States  during  the  ter- 
tiary period,  as  indicated  by  the  character  of  the  organic  remains, 
was  considerably  warmer  than  at  the  present  time.     This  fact  is 
indicated  by  the  character  of  the  fishes,  which  are  generally  lim- 
ited in  their  distribution  by  temperature.     They  are  allied  to  those 
existing  within  the  tropical  seas.     The  sharks,  whose  remains 
are  found  in  Massachusetts,  Maryland,  and  Virginia,  belonged 
to  the  larger  genera,  which  now  live  much  nearer  the  equator. 

In  South  America,  according  to  M.  D'Orbigny,  the  climate  was 
the  same  as  at  present.  In  Europe,  the  character  of  the  fossil 
fruits  of  the  Isle  of  Sheppey  indicates  a  tropical  climate.  This 
difference  of  climate  was  due  to  two  causes :  volcanic  agency, 
and  the  greater  preponderance  of  water  in  the  northern  hemis- 
phere ;  in  other  words,  to 

2.  Physical  Geography. — The  proofs  of  changes  in  physical 

*  According  to  Mr.  Tennant's  catalogue  of  British  eocene  fossils,  there  are 
of  plants  100  species,  and  the  following  species  of  animals : 

Zoophytes 4  species.     Conchifera  and  brachiopoda  .  _  235  species. 

Echinoderms 5       "  Cephalopoda  and  gasteropoda. 267 

Foraminifera 8       "  Fishes 97 

Annelida 11       "          Reptiles 14 

Cirrhopoda 3       "  Birds 1 

Crustacea 4       "          Mammals 14 

Are  all  the  orders  of  animals  found  in  the  tertiary  ?  What  is  said  of  the  re- 
mains of  man  ?  What  was  the  climate  of  the  United  States  during  the  tertiary 
period  ?  How  is  this  known  ?  What  changes  in  physical  geography  ? 


PHYSICAL    GEOGRAPHY   OF    THE   TERTIARY    PERIOD.        207 

geography  since  the  commencement  of  the  tertiary,  and  which 
may  be  traced  directly  to  volcanic  action,  are  found  in  the  north 
of  Italy,  in  Sicily,  in  Spain,  in  Greece,  and  the  neighboring  isl- 
ands, while  in  the  center  of  France  and  on  the  banks  of  the  Rhine 
numerous  extinct  volcanic  craters,  with  their  erupted  materials, 
still  exist.  (See  page  181.) 

In  the  West  India  Islands,  in  Central  America,  and  in  many 
parts  of  the  Andes,  the  changes  produced  by  volcanic  agency 
during  this  period  are  no  less  clearly  indicated  than  in  the  east- 
ern continent. 

It  has  lately  been  shown  by  Sir  Charles  Lyell  that  the  Alps 
have  been  uplifted  since  the  commencement  of  the  eocene  period. 

According  to  M.  de  Elie  de  Beaumont,  there  have  been  five 
principal  directions  of  elevation  during  the  tertiary  period ;  and 
Johnson,  in  his  physical  atlas,  has  given  the  following  view  of 
the  changes  on  sea  and  land : 

"  During  the  epoch,  the  Mediterranean,  or  another  great  and 
corresponding  inland  sea,  covered  the  deserts  of  Sahara,  Lower 
Egypt,  and  part  of  Arabia ;  for  not  till  long  after  the  commence- 
ment of  the  eocene  were  the  present  contours  defined,  and  the 
lagunes  and  ancient  shores  left  dry. 

Later  still,  the  Strait  of  Gibraltar  did  not  exist,  and  the  waters 
of  our  inland  sea  mingled  through  the  channels  of  the  Red  and 
Persian  Gulf  with  those  of  the  Indian  Ocean,  which  seems  to  ex- 
plain the  analogy  of  the  fossils  of  the  middle  and  higher  tertiary 
Mediterranean  beds,  with  creatures  still  living  in  the  Red  and 
Indian  Seas,  and  with  fossils  of  corresponding  age  in  the  great 
basin  of  the  Black  Sea  and  Caspian.  At  the  same  epoch,  too, 
the  North  Sea  and  the  Baltic  spread  over  the  plains  of  Northern 
Europe,  and  another  ocean  stretched  from  the  recesses  of  Siberia 
and  joined  with  the  Mediterranean  by  the  Black  Sea. 

Asia  Minor  contained  small  isolated  basins,  though  the  Black 
Sea  on  the  south  and  east  was  confined  by  its  present  banks. 

When  were  the  Alps  uplifted  ?  How  many  directions  of  elevation  ?  What 
is  said  of  the  Mediterranean  Sea  ?  of  the  Straits  of  Gibraltar  ?  of  other  portions 
of  Europe  and  of  Asia  ? 


208  TERTIARY    PERIOD 

In  the  south  of  Asia  a  broad  sheet  severed  the  peninsula  of  In- 
dia, then  a  triangular  island,  from  the  chains  of  the  Himalaya  and 
their  dependents  ;  and  there  existed  also  a  great  fresh- water  ba- 
sin in  the  peninsula  beyond  the  Ganges,  two  other  basins  at  least 
in  China,  one  on  the  banks  of  the  Lower  Amour,  and  two  in  Si- 
beria. As  in  the  case  of  Europe,  the  center  of  this  continent  was 
covered  by  an  inland  sea,  which  has  now  wholly  disappeared. 
Other  aqueous  masses  covered  Persia,  and  probably  formed,  later 
even  than  the  tertiary  epoch,  one  basin  dependent  on  the  Caspi- 
an, and  another  annexed  to  the  Indian  Sea.  In  another  district 
of  the  continent,  large  portions  of  the  Isles  of  Sunda,  the  Philip- 
pines, Borneo,  New  Guinea,  and  Australia  were  at  this  period 
under  the  waters  ;  and  many  volcanic  peaks,  now  existing  and 
belonging  to  great  areas  of  elevation,  had  not  yet  risen  above  the 
surface  of  the  Indian  or  Malay  Seas. 

Turning  to  the  map  of  America,  we  discern  evidences  of 
changes  equally  singular  and  extensive.  The  Gulf  of  Mexico 
then  penetrated  deep  into  Mexico,  Florida,  the  lower  basin  of 
the  Mississippi,  and  also  into  the  basin  of  the  northern  rivers  of 
South  America.  It  washed  the  southern  extremity  of  the  Alle- 
ghanies  as  well  as  the  foot  of  the  Ozark  Mountains,  and  the  Mex- 
ican and  Columbian  platform.  Further  north,  a  great  interior 
ocean  overspread  a  part  of  this  continent,  comprehending  the 
higher  Mississippi  and  the  great  lakes. 

[The  ocean  washed  the  eastern  margin  of  the  whole  Appala- 
chian chain  in  the  United  States.] 

The  Gulf  of  Mexico  already  contained  a  few  islands  composed 
of  older  formations,  probably  of  much  larger  size  than  those 
whose  shores  it  now  washes,  but  its  volcanic  isles  sprung  into  ex- 
istence subsequently,  during  that  series  of  subsidences  and  eleva- 
tions (of  ecroulements)  of  the  chains  along  the  ancient  shores  of 
South  America,  which  drove  the  sea  from  the  Ozark  Mountains 
and  the  Alleghanies,  and  fixed  its  limits  further  south. 

The  northern  part  of  the  continent  had  three  islands,  the  basin 

What  were  the  general  outlines  of  the  American  continent?  the  Gulf  oi 
Mexico? 


SECONDARY    PERIODS.  209 

of  the  St.  Lawrence  separating  the  district  of  the  Alleghanies 
from  dry  land  on  the  banks  of  Hudson  Bay,  and  perhaps  bend 
ing  round  to  the  icy  sea. 

"  The  platform  of  Mexico  and  Guatemala  formed  an  appendix 
of  the  long  isle  of  the  Rocky  Mountains,  and  the  Ozark  chain 
advanced  into  the  waters. 

"  The  volcanoes  of  Continental  America,  as  we  see  them  now, 
were  cotemporaneous  with  the  formation  of  Mexican  and  Med- 
iterranean basins. 

"  In  South  America  we  discern  abundant  proof  that  at  the  ter- 
tiary epoch  the  Atlantic  covered  the  great  strait  between  Brazil, 
the  Andes,  and  Central  Guayana,  as  well  as  between  the  Pana- 
ma and  the  chain  beyond  the  Orinoco ;  whence  the  mingling  of 
the  tributaries  of  this  and  the  Amazon,  as  well  as  the  mode  of 
the  division  of  the  waters  between  certain  affluents  of  the  La 
Plata  and  the  Amazon.  South  America  was  then  composed  of 
three  great  islands,  for  the  Isthmus  of  Panama  did  not  exist." 

It  is  obvious  that  such  changes  in  physical  geography  as  took 
place  during  this  period  must  have  produced  corresponding 
changes  in  climate. 


CHAPTER  VI. 
SECONDARY  PERIODS. 

HAVING  in  the  preceding  chapter  described  those  deposits 
which  were  made  mostly  in  estuaries,  shallow  seas,  and  fresh- 
water lakes,  we  now  approach  the  shores  of  those  great  oceans 
in  which  were  accumulated  the  materials  that  constitute  a  large 
portion  of  our  present  continents  and  islands. 

The  groups  of  strata  which  lie  immediately  below  the  tertiary, 
and  extend  to  the  base  of  the  triassic,  or  red  sandstone  series,  are 

Of  what  was  South  America  then  composed?  In  wh&t  respects  does  the 
secondary  differ  from  the  tertiary  ? 


210  SECONDARY    PERIODS. 

called  Secondary ',  also  Mesozoic,  because  deposited  during  the 
middle  period  of  geological  history.  The  character  of  these 
groups,  mineral  and  organic,  indicate  conditions  under  which 
they  were  formed,  somewhat  different  from  any  hitherto  con- 
sidered. 

In  passing  from  the  oldest  of  the  tertiary  to  the  newest  of  the 
secondary  rocks,  there  appears  to  be  a  wide  gap,  which  the  in- 
vestigations of  geologists  have  not  as  yet  succeeded  in  filling  up. 
The  chalk  strata  give  abundant  evidence  of  the  action  of  aqueous 
currents,  by  which  their  surface  has  been  eroded  and  large  por- 
tions carried  away,  leaving  the  basins  which  contain  the  oldest 
tertiaries ;  but  the  deposits  formed  by  this  denudation  of  the 
chalk  have  not  been  found — possibly  they  may  be  beneath  the 
present  oceans.  But,  according  to  our  present  knowledge,  the 
close  of  the  secondary  period  terminated  the  ancient  order  of  the 
earth's  surface,  with  all  its  inhabitants,  and  the  beginning  of  the 
tertiary  was  the  commencement  of  an  entirely  new  creation  of 
animals  and  plants,  and  of  essential  modifications  in  the  physical 
geography  of  the  earth. 

In  pursuing  our  investigations,  therefore,  of  the  secondary 
•rocks,  we  take  leave  of  almost  every  thing  that  would  remind  us 
of  the  present  state  of  the  earth.  The  remains  of  the  large  mam- 
malia are  no  longer  found,  and  the  types  of  animal  and  vegetable 
h'fe  are  altogether  new  and  peculiar.  We  appear  to  enter  upon 
a  period  of  the  earth's  history  when  all  of  its  ancient  types  were 
wearing  out,  so  that  not  a  single  species  (if  we  except  a  few  shell- 
fish of  doubtful  species),  and  but  few  genera,  had  sufficient  vital- 
ity to  stretch  across  the  gulf  of  time,  which  separated  the  second- 
ary from  the  tertiary  epoch. 

The  rocks  also  are  more  uniform  in  structure  and  composition, 
and  extend  over  much  larger  areas.  The  tertiary  is  character- 
ized by  its  individuality  ;  the  secondary  by  its  universality.  The 
rocks  of  the  secondary  epoch  are  arranged  in  five  divisions  or 
systems,  each  of  which  is  variously  subdivided : 

What,  is  said  of  the  period  between  the  tertiary  and  secondary?  What 
changes  are  observed  in  entering  upon  the  secondary  periods  ? 


CLASSIFICATION    OF    THE    CRETACEOUS   ROCKS. 


Newer  secondary  ..........      1.  Cretaceous  system. 

f  2.  Wealden. 
Middle  secondary   ..........  |  3    Qolitic  ^^ 

m  ,  (4.  Liassic  series. 

Older  secondary   ...........        '  Triagsic 


SECTION  I.—  CRETACEOUS  SYSTEM. 

The  deposits  of  the  cretaceous  period  are  more  fully  developed, 
and  their  character  has  been  more  thoroughly  studied  in  Europe 
than  in  this  country.  It  may  serve,  therefore,  to  give  a  clearei 
view  of  the  American  cretaceous  system,  if  we  commence  with 
the  European. 

I.  European  Cretaceous  Series.  —  The  several  groups  of  strata 
which  compose  the  cretaceous  system  are  better  developed  in 
England  than  any  other  part  of  Europe.  The  following  table 
will  exhibit  the  order  of  the  several  groups,  and  indicate  their 
geographical  distribution  : 


English,  Danish,  and  Belgian 
series. 

French  series. 

German  series. 

1.  Chalk  of  Faxoe,  Den- 

mark. 

. 

2.  Maastricht  beds,  Bel- 

.1 

gium. 

o 

3.  Uppei'     chalk,     with 

Terrain  senonien. 

Upper  Quader  sand- 

y. 

flints,  England. 

{Terrain  turonien. 

stone. 

8 

4.  Middle     and     lower 

1.  Craie  chloritee.         1 

Upper  Planer  lime- 

S 

chalk  and  clunch,  do. 

2.  Glauconie  crayeuse.  /• 

stone. 

;_ 

5.  Chalk  marl,  do. 

3.  Craie  tufau.                I 

(  Middle  Planer. 

6.  Upper  green  sand,  do. 

(  Lower  Planer. 

7.  Gault,  do. 

Terrain  albien. 

3 
"•Z 

8.  Argillaceous  beds,  do. 

Terrain  aptien. 

1  Lower  Quader 

£ 

-2 

9.  White      and      green  (Argile  plicatules.) 
sandy  beds  and  clay,  i  Terrain  neocomien. 

sandstones. 
Hilsthon. 

i  ' 

do. 

1.  Argiles  bigarrees. 

=3 

10.  Kentish  rasr,  do. 

2.       "        ostreennes. 

Hils-conglomerat. 

g  [11.  Atherfield~clay,  do. 

3.  Calcaire  a  spatangus. 

O 

The  following  section  at  Lulworth  Cove  represents  the  or- 
der of  this  group  in  England,  and  its  connection  with  the  Weal- 
den: 


How  is  the  secondary  divided? 
most  thoroughly  examined  ? 


Where  has  the  cretaceous  system  been 


212  CRETACEOUS    SYSTEM. 

Fig.  91. 


7        65432 
SECTION   AT    LULWORTH    COVE. 

1.  Upper  chalk  3.  Upper  green  sand. 

2.  Lower  chalk.  4.  Gault.  5.  Lower  green  sand 
w^l^n                             5  6-  Purbeck  beds. 

[?.  Hastings's  sand. 

1.  Upper  Chalk. — The  upper  beds  of  the  cretaceous  system 
in  England  consist  of  white  chalk,  which  is  nearly  pure  carbon- 
ate of  lime,  56-5  lime,  43'0  carbonic  acid,  and  0'5  water.     When 
examined  by  a  microscope,  it  is  found  to  be  almost  wholly  com- 
posed of  the  disintegrated  remains  of  infusoria,  zoophytes,  and 
small  shells.     Associated  with  the  beds  of  chalk  are  bands  of 
black  flints.     The  flints  are  generally  in  nodular  masses,  having 
an  organic  nucleus  of  delicate  sponges,  and  of  small  animals. 
They  appear  to  have  been  formed  after  the  deposition  of  the  chalk, 
partly  by  segregation,  and  partly  by  the  passage  of  water  holding 
silica  in  solution,  through  the  chalk  beds,  analogous  to  the  depo- 
sition of  bog- iron  ore  around  organic  bodies  at  the  present  day. 

2.  Middle  and  Lower  Chalk. — The  middle  and  lower  beds  of 
the  chalk  contain  but  few  flints.     The  grains  of  silica  are  distrib- 
uted through  them  with  argillaceous  matter  and  iron,  on  which 
account  they  are  much  more  compact,  and  portions  are  used  for 
the  internal  work  of  cathedrals  and  other  public  buildings.     Thi3 
is  locally  called  CluncJi. 

3.  Chalk  Marl. — The  next  group  is  similar,  being  covered 
with  green  particles  of  silicate  of  iron,  or  dark  red  particles  of 
oxide  of  iron. 

Beds  of  the  same  age  in  Germany  are  marly  limestones  of  a 
gray  color,  and  contain  about  75  per  cent,  of  carbonate  of  lime. 

The  chalk  strata  pass  through  England  from  Hampshire,  in  a 
northeasterly  direction,  to  the  Yorkshire  coast,  separating  into 

Describe  the  upper  chalk.  What  are  associated  with  it  ?  How  were  they 
formed  ?  Describe  the  middle  and  lower  chalk ;  chalk  marl.  Where  is  the 
chalk  found  ? 


LOWER    GREEN    SAND. 

two  spurs  toward  the  east,  which  form  the  North  and  South 
Downs.  The  thickness  is  about  1000  feet.  Across  the  Channel, 
white  chalk  forms  cliffs  on  the  shores  of  France,  opposite  Dover 
and  Beechey  Head  ;  also  in  Denmark,  Poland,  the  south  of  Rus- 
sia, and  the  Caucasus  Mountains.  Cotemporaneous  rocks  in 
Germany  consist  of  loose  sandstones,  with  but  a  few,  about  30 
species  of  fossils,  while  nearly  3000  have  been  found  in  the  En- 
glish chalk  alone. 

4.  Upper  Gredn  Sand. — (3.)  Immediately  beneath  the  chalk  marl 
we  find  a  group  of  argillaceous  and  silicious  limestones,  colored 
green  by  silicate  of  iron,  and  hence  called  green  sand.     This  group 
is  represented  in  Saxony  and  France  by  sandstones ;  some  of 
those  rocks  are  used  for  lining  furnaces,  and  hence  are  called 

"Jire-stone  ;"  others  are  quarried  for  "  whet-stones."     In  the  Isle 
of  Wight  the  beds  attain  a  thickness  of  100  feet. 

5.  Gault. — (4.)  The  gault  is  a  fine  blue  clay,  much  used  for 
bricks.     This  clay,  in  its  lower  beds,  is  filled  with  iron  pyrites, 
and  in  the  upper  with  silicate  of  iron.     The  total  thickness  is  150 
feet. 


5  Weald  clay. 

GREEN    SAND    FORMATION WESTERN    SUSSEX. 

6.  Lower  Green  Sand. — The  lower  green  sand,  marked  5  in 
section,  contains  the  following  kinds  of  strata: 

(1.)  The  first  are  argillaceous  beds,  containing  considerable) 
quantities  of  iron  and  sand. 

(2.)  The  second  group  consists  of  white  and  green  sand,  altern- 
ating with  beds  of  clay. 

(3.)  The  third  stratum  is  a  coarse  limestone,  called  the  Kentish 
rag,  which  is  employed  as  a  rough  building-stone. 

(4.)  Beds  of  dark  clay,  lamellated  in  structure,  and  containing 
nodules  of  clay  iron-stone,  form  the  fourth  and  last  group,  and 

What  is  said  of  the  cotemporaueous  rocks  in  Germany  ?  Describe  the  upper 
green  sand;  the  gault.  Mention  the  kinds  of  rock  in  the  lower  green  sand. 


214  CRETACEOUS    SYSTEM. 

these  repose  directly  upon  the  Wealden,  forming  the  base  of  the 
cretaceous  system.  The  cotemporaneous  rocks  in  France  and 
Germany  are  mostly  sandstones  and  limestones. 

II.  American  Cretaceous  System. — Deposits  of  the  cretaceous 
period  extend  in  the  form  of  a  crescent  from  New  Jersey,  through 
North  and  South  Carolina,  Alabama,  Tennessee,  &c.,  to  Texas, 
a  distance  of  three  thousand  miles.  The  strata  dirj  beneath  the 
tertiary,  and  lie  a  little  west  and  north  of  that  formation.  Cre- 
taceous rocks  also  occur  high  up  the  Missouri  River,  as  far  as  50° 
of  north  latitude,  and  spread  out  toward  the  Rocky  Mountains 
and  New  Mexico,  embracing  an  area  larger  than  any  other  of 
this  formation  on  the  surface  of  the  earth.  The  strata,  however, 
belong  to  the  newer  portion  of  the  cretaceous  system,  lying  be- 
tween the  Maastricht  beds  and  the  gault.  In  Mexico  older  beds 
occur,  and  also  in  South  America,  attaining  a  thickness  in  New 
Granada  of  5000  feet. 

They  extend  along  the  Andes  to  the  extreme  part  of  the  con- 
tinent, in  latitude  53°.  The  strata  are  met  with  high  up  among 
taie  Andes,  attaining  an  altitude  of  13,000  feet  above  the  sea ;  but 
they  do  not  reach  the  plains  either  to  the  east  or  west. 

Character  of  the  Strata. — White  chalk  is  not  found  in  the 
United  States ;  but  instead  of  it,  we  have  sandy  limestones  and 
argillaceous  beds.  The  upper  green  sand  has  an  equivalent  in 
the  green  sand  of  New  Jersey,  which  is  a  stratum  30  or  40  feet 
thick,  spread  over  the  southern  half  of  the  state.  The  green  sand 
is  made  up  mostly  of  grains  about  the  size  of  gunpowder,  of  a 
greenish  color,  and  consists  of  the  following  substances  : 


Silica 49-83 

Alumina 6 

Magnesia 1*83 

Potash 10-12 

Protoxide  of  iron ..    ..21-53 


Water .-...- .9-80 

Loss 0-89 

loo 

Seybert. 


The  silicate  of  iron  and  of  potash  render  it  one  of  the  most 
fertilizing  substances  for  the  land.  Further  south,  in  North  and 

Where  are  the  principal  deposits  of  the  American  cretaceous  system  ?  What 
is  the  character  of  the  strata?  What  is  the  composition  of  green  sand  ?  For 
•what  is  it  used,  and  why  ? 


FOSSILS    OF    THE    CRETACEOUS    SYSTEM. 


215 


South  Carolina,  we  find  thick  beds  of  limestone,  the  proportion 
of  carbonate  of  lime  increasing,  until  in  Texas  the  strata  consist 
of  compact  silicious  limestones.  Lignite  and  numerous  fossils 
are  found  in  many  of  these  beds. 

Fig-  93  is  a  section  showing  the  position  of  the  strata  in  South 
Carolina. 

Fig.  93. 


SECTION   OF    THE    CRETACEOUS    ROCKS    OF    SOUTH    CAROLINA 

We  have  (1st)  the  tertiary  beds;  (2d)  a  bed  of  marl;  (3d) 
marl  stone,  a  stratum  about  three  feet  thick;  (4th)  gray  marl; 
(5th)  shale  ;  (6)  sand  and  blackish  clay.  The  thickness  of  these 
strata  is  very  inconsiderable. 

There  is  abundant  evidence  of  the  erosion  of  these  rocks  by 
water  before  the  tertiary  was  deposited.  A  similar  fact  was  no- 
ticed in  reference  to  the  upper  cretaceous  rocks  in  Europe. 

III.  Fossils  sf  the  Cretaceous  System.  1.  Vegetables.  —  The 
remains  of  vegetables  are  not  very  abundant  in  the  cretaceous 
rocks.  Beds  of  lignite,  however,  occur  in  the  United  States,  and 
many  species  of  Xanthidium  have  been  found  Fig.  94. 

incased  in  the  flint  of  the  chalk. 

Fig.  94  represents  one  of  these  delicate  veg- 
etable bodies  very  highly  magnified.  These 
were  formerly  supposed  to  be  animals.  No.  2 
is  a  thin  transparent  chip  of  flint,  which,  on  be- 
ing viewed  by  transmitted  light  through  a  mi- 
croscope, exhibits  five  Xanthidia.  These  bodies 
vary  from  -g^th  to  j^o^h  °f  an  incn  in  diameter. 
Some  of  the  flint  pebbles  are  filled  with  them,  a 
group  of  20  having  been  found  in  an  area  of  a 
line  in  diameter.  They  appear  as  globular  bod- 
ies, with  minute  branches,  as  in  the  figure  op- 
posite. It  is  probable  that  they  formed  a  nu- 
cleus around  which  the  silicious  particles  accu-  XANTHIDIUM 
mulated,  and  thus  were  formed  into  permanent  SUM- 

What  fossil  vegetables  occur,  and  in  what  fcrm  ? 


216 


CRETACEOUS    SYSTEM. 


herbaria,  which  the  blights  of  time  can  neither  tarnish  nor  de 
stroy. 

2.  Animals. — We  have  already  observed  that  the  white  chalk 
was  mostly  composed  of  the  remains  of  infusoria,  small  corals, 
and  shell-fish. 

(1.)  According  to  M.  Ehrenberg,  a  cubic  inch  of  chalk  may 
contain  upward  of  one  million  of  well-preserved  animal«ulites 
and  shells.  In  addition  to  these  microscopic  animals,  great  num- 
bers of  Foraminifera,  small  shells,  spines  of  sponges,  and  of  ech- 
inoderms,  the  scales  and  teeth  of  fishes,  pass  through  the  field  of 
the  microscope.  The  most  abundant  of  the  microscopic  animals 
belong  to  two  genera,  Rotalia  and  Textularia. 

These  are  minute  chambered  shells,  resembling  the  nautilus 
in  form,  but  very  different  in  structure,  as  their  viscera  occupy 
the  separate  chambers  of  the  shell. 

Fig.  95  (2)  represents  fragments  of  a  branched  sponge  in  the 
hollow  of  a  flint  nodule,  and  Fig.  96  the  convex  surface  of  a 
small  coral.  Fig.  97  represents  one  of  the  corals  common  in  the 
United  States,  Anthophyllum  Atlanticum  (Morton). 


Fig.  95. 


Fig.  96. 


Lunulites  radiatus ; 
chalk. 


Fig.  97. 


Anthophyllum  Atlanti- 
cum. 


Branched  sponge  in  flint ;  chalk. 

Many  of  the  flints  derive  their  forms  from  the  form  of  the  pol- 

What  are  the  principal  fossil  animals  of  the  chalk  ?     How  have  they  betffl 
preserved  ?     From  what  have  the  flints  derived  their  forms  ? 


FOSSILS    OF   THE    CRETACEOUS    SYSTEM. 


217 


ype,  which  constitutes  the  nucleus  around  which  the  silicious 
particles  were  collected.  Fig.  98  represents  two  of  these  forms, 
derived  from  a  vcntriculite  called  "petrified  mushroom."  Fig. 
99  represents  the  perfect  animal  in  chalk. 

nr.« 


Ventriculites  in  flint.  Ventriculites  radiatus ;  chalk. 

(2.)  The  remains  of  Echino dermata  are  very  abundant  in  the 
upper  part  of  the  cretaceous  rocks ;  stone-lilies,  star-fishes,  and 
sea-urchins  are  the  principal  families,  and  are  represented  in  the 
accompanying  figures  of  English  fossils.  Goniaster  semilunata 
(chalk,  100) ;  Spatangus  cor-anguinum  (chalk  sands,  101) ;  Cidaris 
diadema  (upper  chalk,  102) ;  Ananchyles  ovatus  (upper  chalk, 
103). 


Fig.  101. 


Fig.  100. 


Spatangus  cor-anguinum 
Fig.  102. 


Star-fish— Goniaster  semilunata. 


Cidaria  diadema. 


Where  are  the  remains  of  echinodermata  abundant  ?     Mention  the  princi 
pal  families. 

K 


218 


CRETACEOUS    SYSTEM 


Fig.  103. 


Fig.  104. 


Ananchytes  ovatus. 

Fig.  104  represents  the  interior  of  an  ananchytes,  with  flint  on 
the  bottom  and  crystals  of  calcareous  spar  around  the  sides  and 
top. 

(3.)  Mollusca. — The  fossil  shells  of  the  cretaceous  period  are 
very  numerous,  and  are  confined  mainly  to  salt-water  species. 
The  remains  of  Terebratulce  abound  in  the  white  chalk  and 
green  sand.  These,  with  several  species  of  ostrea,  Fig.  105,  and 
plagiostoma,  Fig.  106,  appear  to  be  characteristic  of  this  group. 

Fig.  107. 

K 


Ostrea  carinata ;  up- 
per green  sand. 


Plagiostoma  spinosum ; 
upper  chalk. 


Beleranites  mucro- 
natus ;  chalk. 


Many  of  the  fossil  shells  of  this  period  are  allied  to  the  nauti- 
lus and  to  the  cuttle-fish. 

The  most  remarkable  of  them  are  the  Belemnites,  which  are 
long  cylindrical  stones  of  calcareous  spar,  somewhat  pointed  at 
one  extremity,  and  containing  a  hollow  cup  at  the  other,  Fig. 
107.  Many  species  are  transparent,  others  nearly  opaque. 
When  broken,  they  present  a  radiated  structure  (2).  The  ani- 

What  was  the  character  of  the  mollusca  of  this  period  1  What  are  the  most 
remarkable  shells  of  this  period  1 


FOSSILS    OF    THE    CRETACEOUS   SYSTEM. 


219 


mal  resembled  the  cuttle-fish ;  the  sheath  or  pen  containing  an 
ink-bag  was  inclosed  within  the  body  of  the  animal. 

The  bed  of  marl  marked  4  in  Fig.  93  is  so  filled  with  belem- 
nites  that  they  appear  to  be  driven  into  the  bluff  as  thickly  as 
possible. 

Of  those  related  to  the  nautilus,  the  two  principal  families 
are  the  Nautilidce  and  the  Ammonitidce.  The  following  figures 
present  several  forms,  and  are  good  representations  of  those  fam- 
ilies. 


m  in. 


All  the  shells  of  these  families  are  di- 
vided internally  into  many  compartments, 
by  partitions,  through  which  a  tube  ex- 
tends from  the  outer  open  chamber  to 
3   the  innermost  cell.     This  tube  is  called 
8,  the  siphuncle.    The  outer  chamber,  which 
=f  is  much  larger  than  the  others,  was  occu- 
|  pied  by  the  animal. 
2,       The  siphuncle  of  the  nautilus  is  situ- 
1   ated  either  in  the  center  or  inner  mar- 
,§   gin ;  that  of  the  ammonitidae  upon  the 
|-  outer  margin  or  back  of  the  shell.     When 
the  shell  of  the  ammonitidae  is  regularly 

Hamites  cylindraceus.  coiled  up>   ag    jn  ^  1Q9?  ^    gemjs   jg 

Ammonites;  when  each  end  is  rolled  up,  as  in  Fig.  110,  Sea- 
phites;  when  coiled,  as  in  Fig.  Ill,  Hamites;  and  when  straight, 
Baculites.  Other  genera  have  different  forms. 

How  are  the  shells  of  these  families  divided  ?    How  are  they  distinguished  f 


220 


CRETACEOUS    SYSTEM. 


Some  of  these  shells  are  peculiar  to  the  gault,  and  others  to  the 
chalk.  They  extend  from  the  earliest  palaeozoic  through  the  sec- 
ondary periods,  but  not  into  the  tertiary  period. 

(4.)  Articulata.  —  A  very  rare  species  of  Balanus,  supposed  to 
belong  to  the  chalk,  is  represented  in  Fig.  112.  Grabs  occur  in 


Fig.  114. 


Loricula  pulchel- 
la;  chalk. 


Corystes  Stokesii ;  gault. 


Ptychodus  Mortoni ;  New  Jersey. 


the  gault,  Fig.  113,  and  lobsters  in  the  chalk.     Fig.  115  repre- 
sents the  claw  of  Astacus  Sussexiensis  ;  chalk  ;  England. 

Fig.  115. 


Chelate  claw  of  Astacus  Sussexiensis. 

(5.)  Fishes. — The  teeth  of  sharks  are  very  common  in  the  chalk 
and  the  cretaceous  rocks  of  the  United  States.  They  belong  to 
the  same  genera  with  those  already  described,  but  the  species 
are  believed  to  be  all  different ;  Fig.  114  is  the  tooth  of  Ptycho- 
dus Mortoni,  N.  J.  The  vertebrae,  jaws,  scales,  and  teeth  of 
many  other  families  are  frequently  met  with.  Some  very  singu- 
lar forms  are  found  in  the  United  States,  and  in  the  chalk  of  En- 
gland. The  fossil  fishes  of  the  chalk  are  obtained  with  great  dif- 
ficulty, in  consequence  of  the  friable  nature  of  the  rock.  The 


Where  do  they  belong?     Mention  examples  of  articulata.     What  teeth  are 
tommon  in  the  cretaceous  rocks  1     What  is  said  of  the  fossil  fishes  ? 


FOSSILS    OF   THE    CRETACEOUS    SYSTEM.  221 

most  remarkable  remains  of  fishes  are  their  coprolites  (fecal  re- 
mains). It  has  been  suggested  that  a  large  portion  of  the  chalk 
has  been  passed  through  the  bodies  of  fishes. 

Darwin  found  that  certain  fishes  in  the  Pacific  Ocean  fed  upon 
the  coral  zoophytes,  and  that,  when  they  were  caught  and  open- 
el,  the  substance  contained  within  them  could  hardly  be  distin- 
guished from  chalk. 

(6.)  Reptiles. — The  remains  of  crocodiles  and  of  several  other 
reptiles  are  common  to  the  cretaceous  system  and  the  oolites; 
but  the  most  characteristic  reptile  of  the  chalk  is  the  Mososaurus. 
Teeth  of  this  animal  have  been  found  in  the  United  States,  and 
four  or  five  vertebras  in  the  English  chalk ;  but  the  head,  with 
the  teeth,  was  discovered  in  a  quarry  at  Maastricht,  Fig.  116. 
It  is  now  in  the  museum  at  Paris,  having  been  carried  thither  bv 
the  savans  under  Napoleon. 

Fig.  116. 


MOSOSAURUS. 

This  aquatic  reptile  was  about  25  feet  in  length.  It  probably 
had  webbed  feet,  and  a  tail  suited  to  propel  it  through  the  wa- 
ter. Cuvier  supposed  that  it  inhabited  the  ocean. 

The  Leiodon  was  similar,  and  several  reptiles  more  nearly  al- 
lied to  lizards  than  crocodiles  occur  in  the  chalk ;  also  the  re- 
mains of  turtles,  consisting  mostly  of  the  shells  of  the  animals. 

What  other  remains  of  fishes  ?  What  observation  of  Darwin  ?  What  rep 
tile  peculiar  to  the  chalk  ?  What  otVer  reptiles  abound  ? 


222  WEALDEN    FORMATION. 

Some  specimens  found  in  the  lower  chalk,  at  Burnham,  Kent,  are 
remarkable  for  their  fine  state  of  preservation. 

The  remains  of  birds  and  mammalia  are  not  found  in  the  chalk* 
As  it  is  a  marine  formation,  we  should  not  expect  to  find  any  but 
those  of  seals,  and  whales,  and  other  cetaceans ;  but  these  prob- 
ably did  not  exist  during  this  period — they  commenced  with  the 
tertiary,  which  was  the  age  of  mammals,  while  the  deposition  of 
the  chalk  terminated  the  reign  and  the  age  of  reptiles. 

SECTION  II — WEALDEN  FORMATION. 

The  rocks  of  this  group  are  of  fresh-water  origin,  and  with  a 
few  exceptions  are  confined  to  the  southeast  of  England. 

The  Wealden  is  interposed  between  the  oolitic  and  the  creta- 
ceous system,  but  from  the  character  of  its  fossils  it  is  consider- 
ed by  most  geologists  as  a  part  of  the  oolitic  group. 

I.  Composition. — It  is  composed  of  a  series  of  clays  and  sands, 
and  rests  on  beds  of  imperfect  limestone  and  shells,  through  which 
are  distributed  fresh- water  shells,  terrestrial  plants,  and  the  teeth 
and  bones  of  reptiles  and  fishes.  Univalve  shells  are  mostly  con- 
fined to  the  upper,  and  bivalve  to  the  lower  division,  while  the 
remains  of  reptiles  occupy  the  intermediate  beds.  It  appears  to 
be  an  estuary  deposit.  The  following  are  the  principal  divisions : 

1.  Weald  clay.     2.  Hastings  sand.     3.  Purbeck  strata. 

1.  Weald  Clay. — This  group  consists  of  beds  of  sandstone  and 
shelly  limestones,  with  layers  of  argillaceous  iron  stone.     The 
limestone  is  called  Sussex  marble,  and  is  found  in  layers  from  a 
few  inches  to  a  foot  in  thickness,  separated  from  each  other  by 
thin  seams  of  clay  and  coarse  limestones.     It  is  composed  almosf 
entirely  of  the  shells  of  paludina,  cemented  by  lime  into  a  com- 
pact  marble.     The  clay  is  only  remarkable  for  being  favorable 
to  the  growth  of  the  oak,  and  hence  called  by  Dr.  Mantell  "  oak- 
tree  clay." 

2.  Hastings  Sand. — This  group  is  of  fresh-water  origin,  and  i* 

Are  there  any  birds  or  mammals  found  in  these  deposits  ?  Where  is  thw 
Wealdeu  group  developed?  Of  what  is  it  composed?  Describe  the  Wealt* 
clay;  the  Hastings  sand. 


FOSSILS    OF    THE    WEALDEN. 


22ft 


the  most  important  of  all  the  Wealden  deposits,  not  only  on  ac 
count  of  its  greater  thickness  and  extent,  but  also  for  the  fossils 
which  it  contains.  It  consists  of  numerous  strata  of  sand,  sand- 
stones, grit,  and  shells.  The  upper  beds  form  a  group  the  most 
noted  and  interesting,  because  of  the  extensive  quarries  in  Til- 
gate  Forest,  near  Horsham,  in  which  have  been  discovered  the 
most  remarkable  fossils  of  this  period. 

3.  PurbecJc  Strata. — The  Purbeck  strata  constitute  the  base 
of  the  Wealden,  and  in  many  places  seem  to  pass  into  the  next 
group,  so  that  it  is  often  difficult  to  determine  to  which  system 
many  of  the  beds  belong. 

The  following  section  of  the  quarries  in  the  Isle  of  Portland 
will  exhibit  the  order  of  these  strata : 

The  Purbeck  strata  may  be  divided  into 
two  parts.  The  upper  beds  consist  of  fis- 
sile limestones,  abounding  with  fresh-water 
shells  of  the  genus  Cyclas.  The  limestones 
alternate  with  beds  of  clay,  and  include  a 
thick  bed  almost  entirely  composed  of  oys- 
ter shells.  There  are  about  fifty  beds  of 
limestone,  which  are  quarried  for  building 
materials.  The  whole  series  is  not  less  than 
150  feet  in  thickness. 


Fig.  117. 


SECTION.      ISLE   OF   PORTLAND. 

1.  Purbeck  series. 


2.  Portland  beds. 


The  lower  beds  are  coarse,  fissile  limestones,  used  for  roofing 
purposes,  and  associated  also  with  beds  of  clay. 

The  section  at  Lul worth  Cove,  page  212,  gives  the  relations 
of  the  Wealden  to  the  cretaceous  and  also  to  the  oolitic  system. 
The  Wealden  is  principally  found  in  the  counties  of  Kent  and 
Sussex,  and  in  the  Isle  of  Wight. 

In  the  northwest  of  Germany,  a  series  of  strata  800  feet  in 
thickness  has  been  referred  to  this  period,  but  the  deposit  has  a 
very  limited  geographical  distribution,  being  confined  mainly  to 
a  narrow  strip  in  England. 

Describe  the  Purbeck  strata.  How  is  the  Purbeck  strata  divided?  Are 
there  other  strata  belonging  to  the  Wealden  ? 


224  WEALDEN    FORMATION. 

II.  Fossils  of  the  Wealden. — The  fossils  of  this  period  belong 
to  land  animals  and  vegetables,  or  to  species  inhabiting  fresh- 
water rivers,  estuaries,  and  lakes.  The  number  of  species  is  not 
large,  but  the  individuals  are  very  abundant,  although  rather  im- 
perfectly preserved. 

1.  Vegetables. — The  fronds  of  ferns  or  of  cycadeae,  and  the  si- 
licified  trunks  of  large  coniferous  trees,  are  frequently  met  with 
in  the  Wealden  strata ;  but  the  most  characteristic  genera  are 
clathraria  and  endogenites. 

The  Clathraria,  Fig.  118,  had  a  thick  epidermis  or  false  bark, 
formed  by  the  union  of  the  basis  of  the  leaves,  and  covered  by 
distinct  scales. 

Fig.  118. 


CLATHRARIA  LYELLI  (MANTELL). 

The  Endogenites  are  elongated  flattened  bodies,  tapering  ai 
both  extremities,  and  sometimes  measuring  8  feet  across.  They 
consist  of  two  portions,  a  stony  nucleus  and  a  crust  of  lignite. 

2.  Animals. — The  fossils  of  this  period  belonging  to  the  inver- 
tebrate animals  do  not  possess  much  interest,  as  they  differ  but  lit- 
tle from  those  inhabiting  the  rivers  and  estuaries  of  the  present  day. 

The  shells  of  molluscs  are  chiefly  referable  to  extinct  species 
of  cyclas,  melanopsis,  and  paludina.     Entire  beds  are    F}o,  119 
often  composed  of  single  species  of  each  of  these  genera. 

Crustaceans  are  abundant,  but  are  mostly  confined  to 
the  genus  Cypris,  and  a  new  genus  of  Isopoda,  Fig.  119, 
which'  is  allied  to  the  trilobites  of  the  palaeozoic  periods. 

The  insects  are  chiefly  beetles,  and  a  few  genera  be- 
longing to  families  which  live  on  plants  or  hover  over 
the  surface  of  water.  Wealden. 


What  was  the  character  of  its  animals  and  plants  ?     What  vegetables  ara 
characteristic  of  it  ?     What  is  said  of  the  invertebrate  animals  ? 


FOSSILS    OF    THE    WEALDEN.  225 

The  remains  of  Jtsh  consist  mostly  of  imperfect  fragments, 
which  have  been  referred  to  13  species.  They  appear  to  have 
inhabited  shallow  and  muddy  water. 

The  most  interesting  and  remarkable  fossils  of  the  Wealden 
are 

The  Remains  of  Reptiles. — About  one  sixth  of  the  whole  num- 
ber of  extinct  reptiles  belong  to  this  period,  and  five  genera  be- 
longing to  three  orders  are  peculiar  to  it.  The  SucJwsaurus  and 
Goniopholis  are  referred  to  the  crocodilian  order  of  Owen.  The 
Iguanodon  and  Hylaosaurus  to  the  order  Dinosauria.  The  Tre- 
tosternon  and  some  other  turtles  to  the  order  Chelonia.  A  few  oth- 
er reptiles  existed  in  this  period,  which  also  are  found  in  the  oolite. 

The  Suchosaurus  was  a  long-snouted  crocodile  resembling  the 
gavial  of  the  Ganges.  The  crowns  of  its  teeth  were  slender, 
compressed,  and  acute. 

The  Goniopholis  was  more  nearly  allied  to  the  short-snouted 
crocodile,  with  teeth  whose  crowns  were  round  and  obtuse.  This 
singular  animal  was  covered  with  large  bony  scales,  more  per- 
fectly and  powerfully  arranged  than  those  of  any  known  reptile 
living  or  extinct. 

The  Hylceosaurus  (Wealden  lizard)  was  a  land  saurian  15  feet 
in  length,  and  covered  with  elliptical  scales.  Dr.  Mantell  obtain- 
ed a  large  portion  of  the  skeleton  of  this  animal  from  the  quarries 
of  Tilgate  Forest. 

The  Iguanodon,  the  largest  and  most  remarkable  of  the  extinct 
reptiles  either  of  the  "Wealden  or  of  any  other  period,  was  first 
discovered  by  Dr.  Mantell  in  the  quarries  of  Tilgate  Forest.  It 
was  at  first  described  by  him  as  a  reptile  100  feet  in  length,  and 
in  consequence  of  its  resemblance  to  the  modern  iguana  he  called 
it  Iguanodon.  Its  structure,  however,  differs  from  any  living 
reptile,  and  later  discoveries  have  shown  its  length  to  have  been 
much  less  than  it  was  at  first  supposed.  But  it  is  still  regarded 
as  one  of  the  most  gigantic  of  the  reptiles  of  the  ancient  world, 
It  was  herbivorous,  and  from  25  to  50  feet  in  length. 

What  is  said  of  the  reptiles  ?  Mention  the  several  orders  of  reptiles.  D» 
scribe  them  in  order  Which  was  the  largest  ? 

K2 


226  OOLITIC    SYSTEM. 

The  length  of  the  head 3  feet. 

trunk 12     " 

«  tail 13     " 

28. —  Owen. 

The  bones  are  very  large,  the  legs  and  feet*  being  of  gigantic 
proportions,  suited  to  sustain  the  immense  weight  of  its  body. 

The  Tretosternon  had  a  shell  similar  to  turtles,  although  very 
flat,  measuring  in  one  species  17  inches  by  13£.  Turtles  are 
common  in  the  quarries  of  Tilgate. 

Birds  are  few,  and  their  remains  are  imperfectly  preserved. 

The  characteristic  fossils  of  this  period,  it  will  be  seen,  are  rep- 
tiles which  are  so  far  removed  from  existing  forms  that  it  is  diffi- 
cult to  derive  any  satisfactory  account  from  them,  either  of  the 
physical  geography  or  of  the  climate  of  the  period,  during  which 
they  appear  to  have  been  the  undisputed  lords  of  the  habitable 
earth. 

SECTION  III.— OOLITIC  SYSTEM. 

The  term  oolite\  is  applied  to  a  series  of  strata  constituting  a 
formation,  on  account  of  the  structure  of  some  of  the  limestones, 
which  are  made  up  of  small  egg-shaped  particles.  The  oolite  is 
composed  essentially  of  limestones,  clay,  and  sandstones.  Some 
of  the  lower  beds  contain  valuable  seams  of  coal. 

I.  Oolite  of  the  United  States. — The  only  deposit  in  this  coun- 
try which  has  been  referred  to  this  period  is  found  in  Eastern 
Virginia.  The  strata  consist  of  conglomerates,  sandstones,  and 
beds  of  coal.  The  coal-field,  of  which  Fig.  120  is  a  section,  con- 
stitutes the  most  extensive  de-  Fig.  120. 
posit  of  coal  that  has  been  dis- 
covered  in  any  of  the  forma-  SECTION  OF  THE  COAL-FIELD,  E.  VA. 
tions  which  are  newer  than  those  of  the  carboniferous  system. 
The  area  has  been  estimated  at  185  square  miles.  The  depth, 

*  The  metacarpals  were  2  feet  6  inches  in  length,  and  the  last  joint  of  the 
toe  5^  inches. 

t  uov,  an  egg ;  2.i6o£ ,  a  stone.  This  structure  is  not  confined  to  the  rocks  of 
this  system,  but  occurs  in  the  tertiary  and  some  other  rocks. 

From  what  is  the  term  ooTite  derived  ?  Describe  the  oolites  of  the  United 
States. 


UPPER    OOLITES. 


227 


excepting  at  the  skirts,  is  unknown.  The  central  portions  are 
covered  by  conglomerates,  and  the  coal  rests  on  a  series  of  sand- 
stones. Three  seams  have  been  explored,  the  total  thickness  of 
which  varies  from  11  to  40  feet.  The  coal  is  bituminous,  and  is 
divided  into  thin  horizontal  layers,  as  in  the  older  coal  beds. 
"  Sometimes  thin  layers  consist  alternately  of  highly  crystalline 
and  resinous  coal,  with  a  bright  luster,  and  of  other  portions  ex- 
actly resembling  charcoal  in  appearance." 

II.  European  Oolite. — In  England  we  have  the  most  perfect 
development  of  this  system,  consisting  of  three  ridges,  running 
northeast  and  southwest,  with  extensive  intervening  plains.  The 
rocks  are  divided  into  three  groups,  the  upper,  the  middle,  and 
Jlie  lower  oolite. 

1.  Upper  Oolites. — This  group  consists  of  three  kind**  of  strata, 
Portland  stone,  Portland  sand,  and  Kimmeridge  clay. 

(1.)  The  Portland  Stone,  found  in  the  Isle  of  Portland,  includes 
several  beds  of  coarse  earthy  limestone,  which  repose  upon  sili- 
cious  beds  containing  green  sand,  and  hence  called  Portland  sand. 
The  lower  limestones  are  coarse,  alternately  hard  and  soft,  and 
50  or  60  feet  in  thickness.  Upon  these  repose  three  beds  of  fine 
building  stones  interstratified  with  clayey  and  silicious  bands. 

The  upper  part  of  the  series  contains  a  remarkable  deposit, 
called  by  the  workmen  the  dirt  led.  It  consists  of  bluish  loam, 
containing  the  petrifie^  roots  and  stumps  of  trees  in  the  position 
in  which  they  grew,  Fig.  121,  B.  The  stratum  is  only  about  one 

Fig.  121. 


SECTION    OF    THE    DIRT    BED,  ISLE    OF    PORTLAND 


Mention  the  oolites  of  England.     How  are  they  divided  ?     Describe  the 
Portland  stone.     What  remarkable  deposit  in  the  upper  portion? 


228  OOLITIC    SYSTEM. 

foot  in  thickness,  but  extends  over  a  large  area.  It  appears  to 
have  been  formed  about  the  close  of  the  oolitic  period,  the  earth 
having  been  elevated  above  the  water  sufficiently  long  for  the 
formation  of  a  foot  of  soil,  and  for  the  growth  of 'large  trees  ;  after 
which  it  was  converted  into  an  estuary  or  fresh-water  lake,  and 
the  rocks  covered  by  the  Wealden  deposits. 

(2.)  "Portland  Sand. — This  stratum  is  a  silicious  sand,  mixed 
with  green  particles,  attaining  a  thickness,  in  the  western  part  of 
the  Isle  of  Portland,  of  80  feet,  and  interposed  between  the  Port- 
land stone  and 

(3.)  The  Kimmeridge  Clay,  which  is  of  a  bluish  or  grayish- 
yellow  color,  and  contains  selenite,  with  vegetable  and  animal  im- 
pressions. At  Kimmeridge  Bay,  from  which  the  clay  derives  its 
name,  beds  of  highly  bituminous  shale  alternate  with  the  clay. 
The  shale  is  combustible,  and  known  as  Kimmeridge  coal. 

Beds  supposed  to  be  cotemporaneous  with  the  upper  division 
of  the  oolite  are  found  on  the  coast  of  Normandy ;  also  in  the 
upper  strata  of  the  Jura,  in  Switzerland ;  at  Solenhofen,  in  the 
north  of  Bavaria ;  and  on  the  banks  of  the  Donitz,  in  Southern 
Russia. 

2.  Middle  Oolites. — In  this  division,  Fig.  122,  we  find  : 

(1.)  Calcareous  Grits,  or  sand  beds  more  or  less  abounding  in 
calcareous  matter  and  fine  seams  of  clay. 

Fig.  122. 


SECTION    OF    THE    MIDDLE    AND    LOWER   OOLITE. 

(2.)  The  Coral  Rag,  which  consists  mostly  of  calcareous  de- 
posit, derived  from  the  decomposition  of  animal  remains.  Corals 
are  distributed  through  this  rock  in  great  abundance,  particular- 
ly in  Wiltshire,  where  the  bed  attains  a  thickness  of  40  feet. 
The  whole  appears  to  have  been  a  coral  island  in  an  open  sea. 

(3.)  Oxford  Clay. — The  next  group  is  a  stiff  pale-blue  clay, 

What  is  said  of  the  Portland  sand?  of  the  Kimmeridge  clay  ?  What  rocka 
cotemporaneous  with  the  upper  oolites  in  England  ?  What  kinds  of  strata  be 
long  to  the  middle  oolites  ? 


LOWER    OOLITES.  229 

containing  calcareous  matter,  iron  pyrites,  and  numerous  organic 
remains.  These  remains  are  sometimes  found  in  the  clay,  but 
generally  form  the  nucleus  of  the  pyrites.  The  thickness  of  this 
bed  is  about  500  feet.  It  extends  over  a  large  portion  of  En- 
gland. The  Oxford  clay  usually  rests  on  the  corn-brash,  and 
forms  the  basis  of  the  middle  oolites,  but  in  a  few  cases  a  stratum 
from  3  to  5  feet  thick,  consisting  of  calcareous  sandstone,  and 
abounding  in  fossils,  intervenes  ;  the  same  is  true  in  Normandy, 
but  in  Switzerland  the  middle  oolites  rest  on  argillaceous  rocks, 
and  consist  of  strata  which  contain  oolitic  iron  ore  of  great  eco- 
nomical value,  and  also  of  a  limestone  called  Nerincean,  because 
it  is  composed  almost  entirely  of  univalve  shells  of  the  genus 
nerinaea. 

3.  Lower  Oolites. — This  division  of  the  oolitic  series  is  vari 
ously  subdivided  in  England,  but  the  subdivisions  do  not  apply 
to  the  group  in  other  parts  of  Europe. 

(1.)  Corn-brash  is  a  series  of  clays,  sandstones,  and  limestones. 
The  name  is  derived  from  the  excellent  corn  land  formed  by  the 
disintegration  of  the  rock. 

(2.)  The  Forest  marble  is  a  limestone,  sometimes  crystalline, 
and  sometimes* marly,  so  filled  with  organic  remains  that  in  some 
cases  they  constitute  nearly  the  whole  substance  of  the  rock. 

(3.)  The  great  Oolite  consists  of  a  series  of  shelly  limestones, 
alternating  with  fine  soft  freestone,  destitute  of  fossils.  In  the 
upper  strata  the  limestones  are  hard,  of  a  yellowish-white  color, 
and  filled  with  fossils ;  lower  down  they  are  shelly,  and  the  low- 
est are  very  fine  grained  and  almost  crystalline  in  structure. 
This  is  the  most  important  of  the  whole  series,  both  fj  om  its 
furnishing  building  materials  and  for  the  beauty  of  its  fossil 
shells. 

(4.)  The  Bradford  Clay  is  nearly  of  the  same  age  with  the 
preceding.  It  is  a  pale  grayish  clay,  inclosing  thin  slabs  of  a 
tough  brownish  limestone.  It  is  about  60  feet  in  thickness,  and 
often  entirely  absent,  or  interstratified  with  the  underlying  fuller's 

How  are  the  lower  oolites  subdivided  ?  Describe  the  several  kinds  of  rock 
in  ordfr. 


230  OOLITIC    SYSTEM. 

earth.  It  is  remarkable  for  containing  a  peculiar  fossil,  the  Apt- 
ocrinite. 

(5.)  Fuller's  EartJi. — This  is  a  peculiar  kind  of  clay,  used  in 
the  manufacture  of  cloth ;  associated  with  this  is  a  flagging-stone, 
known  as  Stonesfield  slate.  The  latter  occurs  in  two  beds,  sep- 
arated by  a  loose  calcareous  sandstone.  This  strata  has  long 
been  celebrated  for  the  only  remains  of  mammalia  anterior  to 
the  tsrtiary. 

(6.)  The  Inferior  Oolite  consists  of  about  40  or  50  feet  of  cal- 
careous freestone,  reposing  on  friable  sands,  which  constitute  the 
base  of  the  oolitic  system  in  England. 

The  lower  oolites  are  represented  in  several  parts  of  Europe, 
and  in  Eastern  Virginia,  United  States,  already  described  as  con- 
taining coal.  The  Brora  coal  is  referred  to  the  older  oolitic  pe- 
riod. This  coal  has  been  mined  for  250  years.  It  has  two  work- 
able seams,  the  main  seam  being  about  three  and  a  half  feet 
thick.  There  are  several  coal-fields  in  India,  which  probably 
belong  to  this  period. 

4.  Oolites  of  the  Jura. — The  Jura  Mountains  are  separated 
from  the  higher  Alps  by  the  great  valley  of  Switzerland.  In  the 
northern  part  of  this  range  we  have  a  beautiful  development  of 
the  Oolitic  or  Jurassic  system.  The  rocks  here  are  inclined  at  a 
high  angle,  Fig.  123,  and  are  divided  into  three  groups. 

Fig.  123. 


2        3        Lias.  Lias.  3 

SECTION   ACROSS    THE  |  JURA    CHAIN. 

1.  Coralline  limestone.  2.  Argile  d'Oxford,  or  Oxford  clay. 

3.  Inferior  oolite. 

(1.)  The  upper  beds  resemble  the  Portland  rocks  and  the 
Kimmeridge  clay,  but  contain  great  quantities  of  iron  ore,  which 
abounds  through  a  vertical  depth  of  about  40  feet  of  the  strata. 

(2.)  The  middle  beds  are  more  than  300  feet  thick,  and  differ 

Wheie  are  the  inferior  oolites  found,  and  what  do  they  contain?  Where 
ar«  the  lower  oolites  represented  ?  Describe  the  oolites  of  the  Jura, 


FOSSILS    OF    THE    OOLITE.  23] 

much  from  the  corresponding  beds  in  England.  These  most  im- 
portant strata  consist  of  an  oolitic  iron  ore  in  beds  of  marl  one 
hundred  feet  thick,  and  the  Nerin&an  limestone,  which  corre- 
sponds to  the  coral  rag. 

(3.)  The  lower  oolites  of  the  Jura  are  about  300  feet  thick,  and 
are  subdivided  into  four  groups,  consisting  mostly  of  limestones, 
alternating  with  marls  and  yellowish  clay,  and  also  with  shaly 
bands  and  red  oxide  of  iron. 

In  the  north  and  center  of  Germany,  instead  of  the  Kimmer- 
idge  clay  there  occurs  in  Bavaria,  near  Solenhofen,  a  very  fine- 
grained limestone  of  a  rich  cream  color,  which  is  extensively 
used  for  the  purposes  of  lithography,  and  exported  to  most  parts 
of  Europe.  This  lithographic  rock  rests  on  a  stratum  which  is 
celebrated  for  its  caverns,  and  for  the  beauty  of  the  fossil  insects 
that  have  been  preserved  in  the  stone. 

III.  Fossils  of  the  Oolite. — We  have  noticed,  page  226,  the  ex- 
tensive beds  of  coal  derived  from  the  plants  which  flourished  dur- 
ing this  period.  The  vegetables  differ  from  those  found  in  the 
older  coal-beds,  but  are  very  similar  to  those  of  the  succeeding 
periods.  The  Cycadece,  a  tribe  of  plants  now  flourishing  in  the 
tropics,  were  most  abundant.  They  resemble  the  palms. 

Of  the  Animal  relics,  corals  and  salt-water  shell-fish  are  very 
abundant.  Most  of  the  families  of  fishes  and  reptiles  which  are 
found  in  the  chalk  existed  during  this  period. 

The  echinodermata  were  represented  by  many  singular  ani- 
mals, some  of  which,  the  cri-  Fig.  124. 
noideans,  were  star-fishes  that 
were  attached  each  by  a  long 
stem  to  the  rocks  beneath. 

Sea-urchins,  as   echini,  and 
the  genera  diadema,  Fig.  124, 
and  spatangus,  which  are  very 
nearly  allied,  abound  in  vari-       ^^^^^ 
OUS  parts  of  the  oolitic  system.  Diadema  seriate. 

The  higher  orders  of  mollusca  were  very  abundant.    One  spe- 

What  important  deposits  in  Germany  ?  What  is  said  of  the  fossil  plant*  of 
this  period  ?  What  families  of  mollusca  are  abundant? 


232 


OOLITIC    SYSTEM. 


cies  of  ammonite,  from  the  Solenhofen  slate,  Fig.  125,  is  so  per 
fectly  preserved  as  to  give  the  most  Fig.  ISG. 

distinct  outline  of  the  termination  of 
the  aperture.  Fig.  126  is  a  less  per- 
fect specimen. 

Fig.  125. 


Ammonites  semicanaliculatus. 


Ammonites  striatulus  ;  great  oolite. 


Fig.  127. 


In  the  Oxford  clay,  specimens  have  been  found  both  of  the 
ammonite  and  belemnite,  which  have  removed  all  doubt  in  re- 
spect to  the  character  of  these  animals. 

A  specimen  of  belemnite  was  found  in  the  Oxford  clay,  Fig. 
127,  "  in  which  not  only  the  ink-bag,  but  the  muscular  mantle, 
the  head  and  its  crown  of  arms,  are  all  pre- 
served in  connection  with  the  belemnitic 
shell."  Another  specimen  presents  the  con- 
tour of  large  sessile  eyes,  the  tentaculae  arm- 
ed with  a  double  alternate  series  of  horny 
hooks,  and  the  remains  of  two  lateral  fins. 
"  The  belemnite,"  says  Professor  Owen, 
"  having  the  advantage  of  its  dense  but  well- 
balanced  internal  shell,  must  have  exercised 
its  power  of  swimming  backward  and  for- 
ward with  great  vigor  and  precision.  Its 
position  was  probably  more  commonly  vert- 
ical than  in  its  recent  congeners.  It  would 
rise  swiftly  and  stealthily  to  infix  its  claws 
in  the  belly  of  a  supernatent  fish,  and  then 
perhaps  as  swiftly  dart  down  and  drag  its 
prey  to  the  bottom  and  devour  it." 

The  ink-bag  was  doubtless  used  like  that 
of  the  cuttle-fish,  to  discolor  the  water,  and  Anim^Qof 
thus  enable  it  to  escape  from  its  enemies. 

What  was  the  character  of  the  belemnites  ? 


pia ;  Oxford  clay. 


FOSSILS    OF   THE    OOLITE.  233 

Crustaceans  arid  insects  are  admirably  preserved  in  the  litho- 
graphic limestones  of  Solenhofen. 

The  fishes  and  reptiles,  however,  of  this  period  are  objects  of 
the  greatest  interest.  More  than  fifty  species  of  fishes,  belong- 
ing mostly  to  the  sauroid  family,  have  been  found  in  the  various 
oolitic  strata1  of  England.  This  family  includes  those  genera 
which  resemble  the  saurian  reptiles.  The  gar-fish  of  Lake  Cham- 
plain,  Lepidosteus  oxyurus,  is  one  of  the  few  living  species  which 
represent  this  ancient  family. 

Marine  reptiles  were  still  more  abundant  during  this  period. 
The  largest  of  these  tribes  was  named  by  Professor  Owen  Plio- 
saurus.  This  animal  must  have  rivaled  in  size  the  largest  whales. 
The  length  of  that  part  of  the  jaw  in  which  the  teeth  were  in- 
serted was  three  feet,  and  the  conical  teeth  were  seven  inches  in 
length.  The  head  must  therefore  have  been  of  great  size.  The 
neck  was  of  massive  proportions,  some  of  its  vertebrae  being  eight- 
een inches  in  circumference,  although  only  one  inch  in  length,  a 
structure  which  unites  great  strength  and  flexibility.  This  ani- 
mal had  paddles  like  the  whale.  Of  several  other  genera  which 
more  nearly  resembled  the  crocodile  of  the  present  epoch,  the 
Cetiosaurus  was  one  remarkable  for  its  great  size,  the  largest  spe- 
cies being  not  less  than  60  feet  in  length.  This  genus  lived  in 
the  water,  and  was  provided  with  webbed  feet  and  a  broad  vert- 
ical tail,  as  organs  of  motion.  Some  of  the  terrestrial  saurians 
were  allied  to  the  iguanodon.  Of  these, 

The  Megalosaurus  was  the  largest,  attaining  a  length  of  30 
feet.  It  was  provided  with  strong  double-edged  teeth,  curved 
backwaid,  and  serrated  on  both  edges  like  a  saw,  which  admi- 
rably fitted  them  for  holding,  tearing,  and  cutting  up  their  prey. 
The  largest  relic  of  this  animal  is  the  jaw,  Fig.  128,  but  this  is 
sufficient  to  determine  the  character  and  form  of  the  reptile  ;  like 
the  iguanodon,  it  was  probably  elevated  several  feet  from  tho 
ground  on  massive  legs,  which  sustained  a  body  broader  and 
deeper  than  that  of  any  modern  saurian. 

What  is  said  of  the  crustaceans  ?  of  the  fishes  and  reptiles  ?  Describe  the 
marine  reptiles.  Which  was  the  largest  ? 


234 


OOLITIC    SYSTEM, 


JAW    OF    THE    MEGALOSAURUS OOLITE. 


Altogether  the  most  extraordinary  reptile  of  this  period  was 
the  Pterodactyl,  Fig.  129,  an  animal  with  the  form  and  general 

Fig.  199. 


appearance  of  a  bat,  except  its  head,  which  was  very  long,  and 
resembled  that  of  the  crocodile,  to  which  also  the  internal  anat- 
omy of  the  body  corresponded.  Although  the  neck  had  only 
seven  vertebrae,  it  was  so  flexible  that  the  head  could  be  thrown 
over  upon  the  lower  part  of  the  back.  Instead  of  four  toes  ex- 
tended and  enveloped  in  skin,  as  in  the  bat,  the  fifth  toes  only 
were  prolonged,  and  the  skin  extended  along  the  side  of  the  body 
and  legs.  By  this  structure  the  animal  could  fold  its  wings  and 
walk,  or  swim,  or  rise  into  the  air,  as  its  necessities  might  require 

Which  was  the  most  extraordinary  reptile  of  this  period  ? 


HASSIC   SYSTEM. 

The  most  cJiaracteristic  fossils  are  the  remains  of  the  marsupial 
quadrupeds,  found  in  the  Stonesfield  slate,  and  referred  by  Owen 
to  two  genera,  Amphitherium  and  the  Phascolothcrium.  The  jaw 
of  the  latter  is  represented  in  the  accompanying  figure.  These 

Pig.  130. 


JAW    OF    PHASCOLOTHERIUM    (OOLITE) STONESFIELD    SLATE. 

remains  are  the  earliest  proofs  of  the  existence  of  mammals  on 
the  surface  of  our  planet. 

SECTION  IV.— LIASSIC  SYSTEM. 

The  lias  formation  is  found  in  various  parts  of  Europe  and  in 
South  America.  The  strata  are  argillaceous  throughout,  although 
a  considerable  portion  of  calcareous  matter  is  mingled  with  the 
clay,  forming  in  some  places  bands  of  argillaceous  limestone. 

I.  The  subdivisions  of  this  formation  in  England  vary  at  differ- 
ent points,  but  generally  we  find  three  principal  groups,  which 
are  represented  in  section,  Fig.  131,  the  upper,  middle,  and 
lower  lias. 

Fig.  131. 


4  3  2 

SECTION    FROM    THE    SEVERN    TO    THE    COTTESWOLD    HILLS. 

1.  The  Upper  Lias,  also  called  alum  shales,  consist  of  three 
portions.  The  first  and  highest  beds  are  shales  of  a  slaty  struc- 
ture, and  have  long  been  celebrated  for  the  remarkable  fossils 
found  at  Lyme  Regis.  The  middle  portion  is  a  hard  stratum  of 

What  fossils  are  most  characteristic  of  this  period  ?  Where  is  the  liassic 
system  found  ?  How  many  groups  of  strata  are  there  ?  Describe  the  upper 
lias. 


236  LIASSIC    SYSTEM. 

shale  about  thirty  feet  thick,  and  contains  a  large  quantity  of  car- 
bon in  the  form  of  jet,  with  large  fragments  of  the  bituminized 
wood  of  cone-bearing  trees.  The  lower  beds  are  soft  shales,  filled 
also  with  numerous  fossils. 

2.  The  Middle  Lias  consists  of  sandy  shales  about  130  feet  in 
thickness,  through  which  are  distributed  bands  of  argillaceous 
iron  nodules. 

3,  4.  The  Lower  Lias  Shales  consist  of  thick  layers,  finely 
laminated  with  numerous  calcareous  bands  and  concretions,  the 
whole  either  reposing  on  a  whitish  sandstone  of  the  triassic  sys- 
tem, as  in  the  middle  of  England,  or  upon  bluish  marls,  which 
compose  the  upper  layers  of  the  new  red  sandstone  at  Lyme  Re- 
gis, in  the  south  of  England. 

In  the  lower  division  (4)  there  is  a  thin  stratum  almost  entirely 
made  up  of  fossils,  mostly  the  remains  of  fishes.  This  bed  passes 
occasionally  into  sandstone,  which  is  destitute  of  fossils.  The 
fossiliferous  bed  is  nof  more  than  three  inches  in  thickness,  but 
extends  over  a  distance  of  100  miles,  affording  convincing  proofs 
of  a  long  period  of  time  for  their  accumulation. 

II.  Fossils  of  the,  Lias. — The  liassic  system  is  characterized  by 
the  most  remarkable  remains  of  animals  of  any  in  the  whole  se- 
ries of  fossiliferous  strata. 

The  structure  and  composition  of  these  rocks  are  well  suited 
both  to  preserve  and  to  exhibit  the  remains  of  organized  beings. 

1.  The  plants  do  not  differ  essentially  from  those  that  flourish- 
ed in  the  periods  immediately  preceding  or  succeeding,  although 
some  new  and  extraordinary  forms  have  been  discovered. 

2.  Animals. — In  the  absence  of  corals  the  seas  appear  to  have 
been  filled  with  echinodermata,  among  which  the  crinoideans 
were  most  abundant. 

Fragments  of  Pentacrinites,  Fig.  132,  constitute  extensive  beds 
some  inches  in  thickness,  so  perfectly  preserved  that  their  stony 
skeletons  can  be  accurately  traced,  and  the  character  of  the  an- 

Describe  the  middle  and  lower  lias.  What  stratum  in  the  lower  division ! 
What  is  said  of  the  fossils  of  the  lias  ?  of  the  plants  ?  of  the  animals  ?  of  pentao 
rinites  ? 


FOSSILS    OF    THE    LIAS. 
Fig.  132. 


237 


PENTACRINITES    SUBANGULARIS — LYME    REGIS. 

imal  easily  deduced.  This  animal  had  a  five-sided  stem,  from  tlie 
summit  of  which  arms  were  given  off  in  innumerable  ramifica- 
tions, giving  it  the  appearance  of  a  plant.  The  number  of  parts 
of  which  the  skeleton  was  composed  was  not  less  than  150,000 
"  This  animal  is  supposed,  by  Dr.  Buckland,  to  have  been  capa- 
ble of  withdrawing  itself  readily  from  any  substance  to  which  it 
was  attached,  and,  after  floating  about  in  search  of  a  new  and 
more  convenient  resting-place,  fixing  itself  again  upon  the  low- 
er surface  of  some  floating  piece  of  timber." 

The  stomach  formed  a  funnel-shaped  pouch,  composed  of  con- 
tractile membrane,  and  terminated  by  a  small  aperture,  which 

Describe  the  animal. 


238 


LIASSIC    SYSTEM. 


could  be  elongated  and  formed  into  a  proboscis  for  taking  hold  of 
the  food  brought  within  its  reach  by  the  tentaculae,  or  arms  and 
fingers. 

Many  species  of  shell-fish  occur  in  this  formation,  and  three 
species  of  the  genus  Spirifer  are  characteristic  of  it. 

Ammonites,  belemnites,  and  nautili  abound.  Not  less  than 
65  species  of  ammonites,  12  of  belemnites,  and  5  of  nautilus, 
have  been  discovered  in  the  lias  strata. 

From  the  ink-bag  of  one  species  of  belemnites  found  at  Lyme 
Regis,  a  beautiful  pigment  was  prepared,  similar  to  the  India  ink 
which  is  now  obtained  from  the  cuttle-fish,  and  this  fact  has  com 
pleted  the  chain  of  evidence  necessary  to  establish  the  character 
of  these  ancient  races. 

Fishes  and  reptiles  are  the  only  classes  of  vertebrated  animals 
which  have  been  found  in  the  lias.  The  number  of  species  of 
fishes  from  Lyme  Regis  described  by  Prof.  Agassiz  is  not  less 
than  60  ;  all  of  them  are  now  extinct,  and  most  of  them  referable 
to  the  ganoid  and  placoid  orders.  Two  genera,  lepidotus  and 
dapedius,  Fig.  133,  are  the  most  common.  The  remains  offish 

Fig.  133. 


DAPEDIUS  POLITUM;  LIAS. 


belonging  to  the  placoid  order,  called  ichthycdorulites,  are  the 
bony  rays  of  the  fins,  Fig.  134. 


What  evidence  of  the  true  character  of  the  belemnites  ? 
animals  existed  1    What  remains  of  fishes  ? 


What  vertebrated 


FOSSILS    OF    THE    LIA.S. 
Fig.  134. 


239 


ICHTHTODORULITES  J    LIAS. 

The  Reptilian  remains  of  this  period  belong  mostly  to  two 
genera. 

The  Ichthyosaurus  (Jish- Lizard),  Fig.  135,  was  similar  to 

Fig.  135. 


ICHTHYOSAURUS. 

some  of  the  large  predatory  fishes,  but  had  a  much  larger  head 
and  more  powerful  tail,  a  skin  without  scales,  covered  with 
smooth,  fine  wrinkles.  The  head  was  very  peculiar.  The  jaws 
were  so  long  that  the  gape  must  have  exceeded  seven  feet,  and. 
to  give  them  the  requisite  strength,  they  were  made  up  of  a  num- 
ber of  parallel  plates  of  unequal  thickness,  to  enable  thera  to  re- 
sist any  sudden  shock  produced  by  snapping  at  their  prey.  Rows 
of  powerful  teeth  extended  along  both  sides  of  the  jaw,  and  a 
provision  made,  as  in  the  crocodile,  for  renewing  them  when  bro- 
ken or  worn  out.  The  number  of  teeth  found  in  one  individual 
was  180. 

The  eye  was  placed  far  back,  and  its  orbit  was  18  inches  in 
diameter,  having  circular  bony  plates  around  the  pupil  to  defend 
it,  and  to  adapt  it  to  long  and  short-sightedness,  so  that  the  ani- 
mal could  see  equally  well  in  the  water  and  on  the  land.  The 
breathing-holes  were  placed  on  the  top  of  the  head,  in  order  that 
most  of  the  body  might  remain  under  water  during  respiration. 

The  vertebrae  were  like  those  of  fishes,  and  the  ribs  were  small 
and  numerous.  The  extremities  were  paddles,  like  those  of  the 
whale,  though  so  constructed  that  the  animal  could  move  upon 
the  land. 

The  food  of  the  ichthyosauri  was  fish  and  reptiles.     This  is 

What  remains  of  reptiles  ?    Describe  the  ichthyosaurus.    What  was  their  food  ? 


240  LIASSIC   SYSTEM. 

proved  by  the  fact  that  their  half-digested  remains  have  been 
found  in  the  stomach  of  the  animal,  and  not  only  so,  but  copro- 
lites  abound  in  this  formation  similar  to  the  remains  found  in  the 
abdomen ;  in  fact,  these  coprolites,  loaded  with  the  scales,  teeth, 
and  bones  of  fishes  and  reptiles,  constitute  strata  many  miles  in 
extent,  presenting  the  appearance  of  a  conglomerate  rock  com- 
posed of  the  exuvia  of  these  and  other  animals  which  flourished 
during  this  period. 

About  twenty  species  of  this  genus  have  been  described.  They 
commenced  with  the  lias,  and  flourished  until  near  the  close  of 
the  cretaceous  period. 

ThePlesiosaurus,  Fig.  136,  was  another  genus  of  reptiles  still 

Fig.  136. 


PLESIOSAURUS. 


more  peculiar  in  structure.  Its  head  resembled  that  of  a  lizard, 
and  was  quite  small.  Its  neck  was  three  or  four  times  the  length 
of  the  head,  and  contained  upward  of  30  vertebrae.  This  gave  it 
great  flexibility  and  rapidity  of  motion.  The  body  was  small  and 
resembled  a  fish,  and  its  paddles  more  nearly  resembled  those  of 
the  cetaceans  than  those  of  the  ichthyosaurus.  Its  length  was 
about  17  feet.  Eighteen  species  have  been  described,  of  which 
six  belong  to  the  oolitic  and  cretaceous  groups. 

With  the  power  also  of  creeping  on  land,  it  possessed  extraor- 
dinary powers  of  swimming,  which  enabled  it  with  ease  to  over* 
take  its  prey,  while  the  powerful  and  rapid  motions  of  its  wedge- 
shaped  head,  wielded  by  its  long  and  flexible  neck,  rendered  it 
a  match  for  most  of  its  enemies.  That  it  was,  however,  sometimes 
overpowered  by  the  ichthyosaurus,  is  proved  by  the  half-digested 
fragments  of  its  bones  in  the  coprolites  of  the  ichthyosaurus. 

What  is  said  of  the  coprolites  and  other  remains  of  the  animals  of  this  pe- 
riod ?  Give  the  characters  of  the  plesiosaurus.  How  many  species  have  been 
discovered  ? 


TRIASSIC   SYSTEM. 


241 


SECTION  V.— TRIASSIC  OR  NEW  RED  SANDSTONE  SYSTEM. 

The  new  red  sandstone  system  has  received  the  name  of 
Triassic,  from  the  three  well  marked  divisions  of  it  found  on  the 
Continent  of  Europe. 

I.  Geographical  Distribution. — In  the  United  States  this  group 
extends  from  Vermont,  in  the  valley  of  the  Connecticut  River, 
through  Massachusetts  and  Connecticut ;  and  from  New  Jersey 
to  North  and  South  Carolina.     In  England  it  is  principally  de- 
veloped in  the  valleys  of  the  Dee,  Mersey,  and  Weaver.     It  is 
also  found  in  France  and  Germany.     The  strata  appear,  for  the 
most  part,  to  have  been  deposited  in  broad  estuaries. 

II.  Composition  and  Structure. — The  rocks  of  this  system  are 
sandstones,  conglomerates,  and  shales,  and  are  generally  charac- 
terized by  their  color,  which  is  of  various  shades  of  red  and  brown. 
The  strata  are  very  regular,  and  the  rocks  are  often  composed 
of  fine  sand,  and  are  admirably  suited  to  building  purposes. 

III.  Trias  of  North  America. — The  strata  in  the  United  States 
are  separated,  broken  through,  and  overlaid  in  some  places  by 
a  ridge  of  greenstone,  which  forms  mountains  several  hundred 
feet  in  height,  as  those  of  Mount  Holyoke  arid  Tom  in  Massa- 
chusetts, East  and  West  Rock  in  Connecticut,  and  the  Palisades 
in  New  York.     The  structure  of  this  greenstone  is  often  colum- 
nar, like  that  of  the  Giant's  Causeway  and  Fingal's  Cave,  which 
belongs  to  the  same  period. 

Fig.  137. 


b        c 

a.  Pleistocene. 

£.  Mica  slate. 

c.  Calcareo-mica  slate. 

d  d  d.  Red  sandstone. 


e.  Greenstone. 
/.  Gneissoid  mica  slate. 
g.  Granite. 
h.  Gneiss. 
i.  Ichthyolite  shales. 


From  what  is  the  name  triassic  derived  ?  What  is  the  geographical  distri 
bution  of  this  group  in  the  United  States  ?  in  Europe  ?  What  is  said  of  the 
color  and  structure  of  the  rocks  ?  of  intruded  greenstone  ? 

L 


242 


TRIASSIC    SYSTEM. 


In  Massachusetts,  the  trias  lies  in  a  basin  of  metamorphiu 
rocks,  as  represented  in  the  preceding  section,  Fig.  137,  p.  241 
(from  Dr.  Hitchcock's  Report),  across  the  valleys  of  the  Connec- 
ticut and  Deerfield  Rivers.  The  intruded  greenstone  (e)  is  seen 
in  the  middle  of  the  section. 

In  New  York,  the  red  sandstone  is  similarly  associated  with 
greenstone  and  with  metamorphic  rocks,  as  may  be  seen  in  the 
following  section,  Fig.  138,  across  the  Palisades. 

Fig.  138. 


a.  Gneiss  and  granite. 

b.  Red  sandstone  and  conglomerates. 


c  c  c.  Greenstone. 
d  d  d.  Red  sandstone. 


In  New  Jersey,  the  red  sandstone  is  associated  in  the  same 
manner  with  metamorphic  strata  and  with  trap  ridges. 

It  is  obvious  that  the  age  of  these  sandstones  of  the  Northern 
and  Middle  States  can  not  be  inferred  from  their  position.  From 
their  lithological  characters,  and  from  the  fossils,  they  have  rightly 
been  regarded  as  belonging  to  the  triassic  system.  They  are 
deficient  in  salt  and  gypsum,  which  in  Nova  Scotia  and  in  Europe 
occur  more  or  less  abundantly  in  the  rocks  of  this  period. 

Some  geologists  have  thought  it  probable  that  these  rocks  be- 
long to  the  lias  rather  than  to  the  triassic  system.  The  fossil 
fishes  are,  according  to  Mr.  Redfield,  more  nearly  allied  to  li- 
assic  types  than  to  any  types  older  than  the  trias. 

IV.  European  Trias. — The  following  section,  Fig.  139,  across 
a  new  red  sandstone  basin,  from  Oswestry  to  the  north  of  Staf- 
fordshire, in  England,  clearly  exhibits  the  position  and  age  of 
these  rocks. 


p  *  P  m 

«.  Sandstone  and  conglomerates,  reposing  on  Permean  rocks  (pp). 

Describe  the  position  of  the  trias  in  Massachusetts ;  in  New  York,  and  New 
Jersey.     What  is  said  of  the  age  of  this  system  in  the  United  States  ? 


FOSSILS    OF    THE    TRIAS. 


243 


b   Sandstone  and  marls,  which  contain  salt. 

e.  Lower  oolites,  reposing,  in  tne  absence  of  the  lias,  on  the  trias.  Chesh- 
ire is  celebrated  for  its  beds  of  rock  salt,  the  total  thickness  of  which  is  sixty 
feet.  They  alternate  with  beds  of  gypsum,  and  of  blue,  red,  and  brown  in- 
durated clays,  and  with  red  sandstones. 

m  m.  Coal  measures. 

V.  Fossils  of  the  Trias. — 1.  Plants.  In  the  new  red  sandstone 
of  Connecticut,  fossil  trunks  of  trees  have  been  found.  In  Mas- 
sachusetts, a  mass  of  greenstone  of  the  trias,  near  Mount  Hoi- 
yoke,  appears  to  have  enveloped,  while  in  a  melted  state,  a  veg- 
etable stem  two  inches  in  diameter  and  several  feet  long.  The 
cavity  left  by  the  destruction  of  the  stem  was  subsequently  filled 
with  mineral  matter,  which  is  accordingly  destitute  of  organic 
structure.  This  extraordinary  specimen  is  now  in  the  museum 
of  Amherst  College.  Probably  the  process  by  which  the  cavity 
was  formed  was  similar  to  that  described  on  page  56,  as  having 
been  witnessed  during  the  eruption  of  Kilauea. 

In  the  European  trias,  the  remains  of  ferns  have  been  found 
with  the  marks  of  fructification.  Plants  of  the  Zamia  tribe  also 
flourished  in  this  period. 

In  the  triassic  rocks,  some  minute  seams  of  carbon- 
aceous matter  have  been  found,  but  they  are  not  re- 
garded as  indications  of  workable  coal,  for  no  beds 
of  coal  have  yet  been  discovered  in  this  system. 

2.  Radiated  Animals. — Radiated  and  other  animal 
remains  are  found  chiefly  in  the  muddy  deposits  of 
the  trias.  Coarse  sands  are  unfavorable  both  to  the 
growth  and  to  the  fossil ization  of  organic  bodies, 
and  their  remains  are  not  common  in  sandstones. 
Corals,  however,  do  not  flourish  in  muddy  waters,  and 
hence  they  are  rare  in  all  the  rocks  of  this  system. 

One  of  the  most  beautiful  of  the  Crinoideans  of  this 
period  was  the  Lily  Encrinite,  Fig.  140,  remarkable 
for  the  elegance  and  symmetry  of  its  form  and  for  its  moniliformia. 

Describe  the  European  trias.  What  is  said  of  the  fossil  plants  in  the  United 
States  ?  in  Europe  ?  of  coal  ?  In  what  kind  of  strata  are  the  animal  remains 
abundant  ?  in  what  are  they  rare  ?  Describe  the  Lily  Encrinite. 


140. 


244 


TRIASSIC  SYSTEM. 


complicated  skeleton,  which  consisted  of  not  less  than  twenty-six 
thousand  pieces.  The  body  was  supported  on  a  slender  col- 
umn, which  was  attached  at  the  base  to  some  hard  substance  at 
the  bottom  of  the  sea. 

3.  Mollusca. — A  large  portion  of  the  shells  are  such  as  must 
have  inhabited  shallow  water.  The  following  occur  in  the  mus- 
chelkalk  (a  triassic  formation)  of  Europe.  Fiff.  144. 

Fig.  141. 


Myophoria 
vulgar  is. 


Avicula  socialis. 


Ammonites  nodosus. 


4.  Articulata. — Some  extinct  genera  of  crabs  and  lobsters  have 
been  found  in  the  muschelkalk. 

5.  Fishes. — Remains  of  more  than  sixty  species  of  fishes  have 
been  discovered  in  the  European  trias,  chiefly  in  the  muschel 
kalk.     In  certain  bituminous  shales,  which  are  associated  with 
the  red  sandstone  of  the  United  States,  fossil  fishes  are  abundant. 
Th3  most  celebrated  localities  are  at  Sunderland,  in  Massachu- 
setts, and  at  Middletown,  in  Connecticut.     Fig.  145  represents 
the  Catopterus  gracilis,  from  Middletown. 

Fig.  145. 


CATOPTERUS    GRACILIS. 


What  is  said  of  the  shells?  of  the  articulata  ?  of  the  fishes? 


FOSSILS    OP   THE    TRIAS. 


245 


6.  Reptiles. — Remains  of  lizards,  of  marine  saurians,  and  of 
batrachians  occur.  One  of  the  most  extraordinary  reptiles  was 
the  Labyrinthodon.  This  animal  appears  to  have  belonged  to 
the  frog  tribe,  although  it  was  as  large  as  an  ox.  The  bones 
of  the  cranium  and  the  jaws,  and  the  bones  of  the  hinder  ex- 
tremities, show  that  the  genus  was  on  the  type  of  this  order  of 
reptiles,  with  affinities  to  saurians  and  to  fishes.  The  bones  of 
the  legs  and  the  teeth  are  quite  anomalous. 

Fig.  146. 


LABYRINTHODON    JAEGERI. 

a  represents  a  tooth  half  of  the  natural  size ;  b  is  half  of  a.  trans  verse  pol- 
ished section  magnified  twenty  diameters  ;  and  c  is  one  of  the  anfractuosities 
of  b  more  highly  magnified.  The  complicated  structure  of  the  teeth  suggested 
the  name  Labyrinthodon. 

In  the  beds  of  the  same  formation  are  very  singular  quadru- 
pedal footmarks,  which  resemble  a  human  hand,  Fig.  147.  The 
name  Cheirotherium  (hand-beast)  is  therefore  given  to  the  ani- 

Fiff.  147. 


TRACK    OF    THE    CHEIROTHERIUM. 


What  is  said  of  the  reptiles  ?  of  the  Labyrinthodon  ?  of  the  tracks  of  the 
Cheirotherium  ? 


246  TRIASSIC    SYSTEM. 

mal.     The  tracks  of  the  hind  feet  are  much  larger  than  those 
of  the  fore  feet. 

Fig.  148  exhibits  the  manner  in  which  those  tracks  are  sup- 
posed to  have  been  made. 

Fig.  148. 


The  Cheicotherium  and  Labyrinthodon  are  now  supposed  to 
have  been  the  same  animal. 

In  the  red  sandstone  of  the  western  part  of  New  Jersey,  the 
bones  of  a  large  saurian  reptile  have  recently  been  discovered. 

In  the  red  sandstone  of  the  United  States,  and  mostly  in  the 
Connecticut  -River  valley,  numerous  footprints  have  been  found, 
of  which  some  are  referable  to  reptiles  and  others  to  birds  ;  while 
many  so  combine  the  characters  of  both  of  these  classes,  or  are 
otherwise  so  anomalous,  as  to  render  the  precise  character  of  the 
animals  which  made  them  very  doubtful.  These  tracks  had  been 
noticed  for  forty  years  by  persons  who  were  unacquainted  with 
their  nature  and  importance.  In  1835  a  specimen  attracted  the 
notice  of  Dr.  Hitchcock,  who  subsequently  discovered  a  great 
number  of  species,  and  who  has  investigated  their  character  and 
origin  with  great  success.  The  results  obtained  by  him  were  at 
first  received  by  geologists  with  more  or  less  skepticism,  but  aft- 
erward with  admiration,  as  one  of  the  most  extraordinary  and 
interesting  chapters  in  American  Geology. 

These  footmarks  prove  the  existence  of  about  fifty  species  of 
animals,  of  which  twelve  were  quadrupeds  ;  of  these,  four  were 
probably  lizards,  two  were  tortoises,  and  six  were  batrachians. 
Thirty-two  were  made  by  biped  animals,  of  which  eight  were 

"What  is  said  of  the  discovery  of  footmarks  in  the  Connecticut  River  valley  ? 
of  the  number  of  species  ?  of  the  kinds  of  quadrupeds  ?  of  the  kinds  of  biped 
tracks? 


FOSSILS    OF    THE    TRIAS. 


247 


probably  birds  with  three  thick  toes  ;  fourteen  were  birds  with 
three  01  four  slender  toes ;  and  eight  may  have  been  biped  rep 
tiles  !     Of  the  rest,  some  were  made  by  invertebrate  animals,  as 
worms  or  molluscs,  and  others  are  wholly  doubtful.    All  but  two 
of  this  list  occur  in  the  valley  of  the  Connecticut  River. 

The  most  gigantic  of  these  animals  was  a  bird,  which  may  have 
had  some  resemblance  to  the  ostrich  tribe.  It  has  been  named 
Brontozoum  giganteum.  The  feet  were  14  to  20  inches  long, 
and  the  step  was  usually  four  feet  long,  sometimes  six  feet.  The 
nails  of  the  toes  were  If  inches  long.  Some  of  the  tracks  have 

Fig.  149. 


BROXTOZOUM    GIGANTEUM. 


What  is  said  of  the  Brontozoum  giganteum  ? 


248  TRIASSIC   SYSTEM. 

part  of  the  impression  of  the  skin  well  preserved  :  it  seems  to 
have  been  papillose  and  striated.  That  the  bodies  of  these  birds 
were  of  great  bulk,  may  be  inferred  from  the  shape  of  the  foot 
and  from  the  depth  of  the  impression  made  in  the  mud.  Sev- 
eral parallel  series  of  tracks  have  been  found  in  lines  oblique  to 
the  shore  margin.  The  footprints  in  these  series  are  opposite  to 
each  other,  and  thus  show  that  the  animals  walked  in  company 
and  were  gregarious. 

Fig.  149,  p.  247,  represents  a  track  one  fifth  of  the  natural  size. 
Fig.  150.  Fig.  150  (i  natural  size)  represents  the  track 

of  Brontozoum  gracillimum,  a  small  species  of 
the  same  genus.  The  step  was  six  inches 
long. 

Another  large  and  remarkable  biped  species 
was  the  Steropezoum  ingens,  Fig.  151.  This 
animal  had  a  heel,  or  an  appendage  to  the  heel, 
which  left  a  track  resembling  that  of  a  brush. 
The  surface  must  have  been  covered  with 

BRONTOZOUM  ORACH,-  lidSe5  and  striae»  «**"*  than  with  a  brush,  as 
LIMUM.  might  be  supposed  from  the  figure.  The  ani- 

mal was  inferior  in  size  only  to  the  Brontozoum  giganteum  and 
Otozoum  Moodii.  The  length  of  the  foot  was  23  to  25  inches, 
of  the  middle  toe,  10^  inches,  and  of  the  step,  four  to  six  feet. 

A  very  anomalous  track  (Ornithopus  Adamsanus,  Fig.  152)  pos- 
sibly may  have  belonged  to  a  quadruped  of  large  size.  The  foot 
was  13  inches  long.  It  had  a  small  fourth  toe  directed  backward. 

A  large  and  interesting  species  was  the  Polemarchius  gigas, 
Fig.  153,  a  biped  which  had  a  small  hind  toe,  situated  far  back  on 
the  heel,  like  a  spur.  The  long  slender  toes  and  heavy  heel  sug- 
gest both  great  quickness  and  force  of  motion,  for  they  indicate, 
in  the  general  structure  of  the  animal,  long  limbs  and  powerful 
muscles.  If,  as  is  probable,  the  foot  was  used  as  a  weapon  of 
offense  and  defense,  it  must  have  been  a  foimidable  weapon. 

The  most  extraordinary,  and  probably  the  largest  of  all  the 

What  is  said  of  the  Steropezoum  ingens  ?  of  Ornithopus  Adamsanus  ?  of  Pc»- 
lemarchius  gigas  ? 


FOSSILS    OF    THE    TRIA3. 


249 


250 


TRIASSIC   SYSTEM. 


FOSSILS    OF    THE    TRIAS.  251 

animals  of  sandstone  days,  which  Dr.  Hitchcock  has  described, 
was  probably  a  biped  batrachian  or  toad,  with  a  foot  20  inches 
long  and  12  inches  wide.  It  is  obvious  from  the  succession  of 
steps,  as  seen  in  Fig.  154,  that  the  animal  was  a  biped  with  short 
legs.  The  foot  resembled  that  of  an  embryo  frog  more  than 
those  of  any  other  living  animals.  This  form,  in  an  adult  state, 
indicates  an  inferior  grade  of  a  batrachian  type.  Yet  this  bi- 
ped toad  must  have  been  as  large  as  an  elephant.  It  has  been 
named  Otozoum  Moodii.  The  specimen  represented  in  Fig. 
154  (_i_d  natural  size)  was  found  near  Mount  Holyoke,  in  Massa- 
chusetts. It  contains  also  (a  a  and  b  b)  tracks  of  a  species  of 
Brontozoum  (B.  parallel  um),  and  has  much  of  the  surface  pitted 
with  rain-drops,  as  shown  in  the  figure. 

Fig.  155  represents  the  tracks  of  a  small  quadruped,  Anisopus 
gracilis.  The  hind  foot  was  .9  inch  long,  and  the  fore  foot  .55 
inch  long. 

Fig.  155.  Fig.  156. 


Fig.  156  (£d  natural  size)  represents  the  tracks  and  step  of 
another  quadruped,  Anisopus  Deweyanus. 

Numerous  slabs  have  been  found  which  are  more  or  less  cov- 
ered with  tracks.  One  of  the  best  specimens,  from  Turner's 
Falls,  Massachusetts,  was  sold  to  the  British  Museum  by  Dr. 
James  Deane,  of  Greenfield.  A  portion  of  it  is  represented  in 
Fig.  157,  on  page  252.  It  is  about  six  by  eight  feet,  and  con- 
tains 75  tracks. 

In  connection  with  one  kind  of  tracks,  in  Chicopee,  Massachu- 
setts, coprolites  were  found.  They  contain  black  carbonaceous 
grains,  which  are  supposed  to  have  been  undigested  seeds.  Chem- 
ical analysis  shows  these  specimens  to  have  been  the  coprolitea 
of  omnivorous  birds.  Teeth  ascribed  to  a  mammal,  Microlestes 
antiquus,  have  been  found  in  Germany  by  Professor  Plieninger. 

What  is  said  of  the  biped  batrachian  1  of  the  coprolites  from  Chicopee « 


252 


TRIASSIC    SYSTEM. 


PALEOZOIC   PERIODS.  253 


CHAPTER  VII. 

PALAEOZOIC   PERIODS. 

RECEDING  yet  farther  into  the  remote  ages  of  the  past,  we  come 
to  those  formations  which  are  called  Palaeozoic,  because  they 
contain  the  remains  of  the  most  ancient  animals  that  are  known 
to  have  existed.  The  passage  from  the  Mesozoic  to  the  Palaeo- 
zoic formations  is  not  marked  by  any  abrupt  transition  in  the 
lithological  characters  of  the  strata.  Without  fossils,  it  is  even 
difficult  to  find  the  plane  of  division.  Yet  in  the  forms  of  animal 
life,  we  find  a  transition  almost  as  abrupt  as  that  from  the  Ter- 
tiary to  the  Mesozoic.  Although  the  triassic  strata  (the  oldest 
Mesozoic)  usually  repose  conformably  on  the  Permean  rocks  (the 
newest  Palaeozoic),  yet  the  fossils  are  entirely  different.  Not  one 
of  the  species  which  existed  during  the  Permean  epochs  was  con- 
tinued into  the  trias. 

Some  of  the  Permean  animals  had  existed  through  several  of 
the  previous  Palaeozoic  periods,  and  most  of  the  others  were 
nearly  allied  to  their  more  numerous  predecessors.  The  species 
of  the  last  Palaeozoic  period  may,  therefore,  be  regarded  as  the 
remnant  of  older  types,  which  were  gradually  dwindling  away. 
In  the  later  Palaeozoic  periods,  the  dawn  of  a  new  order  of  things 
was  seen  in  the  introduction  of  a  few  species  of  saurians,  a  tribe 
of  reptiles  which,  as  we  have  seen,  had  an  enormous  develop- 
ment during  the  Mesozoic  periods.  Thus,  as  we  go  up  the 
stream  of  time,  we  find  all  the  genera,  and  even  some  entire  fam- 
ilies and  orders  disappearing,  and  others  taking  their  place. 


What  is  said  of  the  transition  fron. 
?  oft 
mean  fossils     of  the  introduction  of  Saurians? 


the  Mesozoic  to  the  Palaeozoic  formations  ?  of  the  general  character  of  the  Pel 


254 


PERMIAN    SYSTEM. 


SECTION  I.—  PERMEAN  SYSTEM. 

I.  Geographical  Distribution.  —  This  system  derives  its  namo 
from  the  ancient  kingdom  of  Permea,  in  the  eastern  part  of  Rus- 
sia in  Europe,  where  the  rocks  of  this  period  occupy  a  district 
700  miles  long  from  north  to  south,  and  nearly  400  miles  wide. 
It  is  also  well  developed  in  England  and  France  ;  but  it  is  in 
Germany  especially  that  it  appears  with  a  numerous  series  of 
well-marked  subdivisions. 

II.  Structure  and  Position.  —  These  rocks  consist  of  many  dis- 
tinct strata  of  various  characters.     They  are  composed  of  white 
limestone,  with  gypsum  and  rock  salt,  sandstones  with  slates  and 
copper  ore,  of  magnesian  limestone,  conglomerates,  &c. 

Fig.  139  (page  242)  exhibits  the  position  of  the  system  in  the 
rocks  of  England.  The  following  figure,  exhibits  their  subdivi- 
sions in  Germany. 

Fig.  158. 


SECTION   OF   MAGNESIAN    LIMESTONE    (GERMANY). 

f  Zechstein, 


Shaly 


7.  Letten;  clay. 
6.  Fetid  limestone. 

5.  Rauwacke,  cellular  magnesian  limestone 
4.  Argillaceous  schist. 
3.  Bituminous  schist  and  copper  slate. 
2.  Arenaceous  schist. 
Lower  new  red  series 1.  Rothe-todte-liegende.* 

III.  Fossil  Plants. — The  species  are  not  numerous.     A  few 
of  them  are  identical  with  the  species  of  the  carboniferous  sys- 
tem, and  the  others  belong  to  the  genera  of  that  system. 

Fig.  159  represents  a  species,  Odontopteris  Strogonovi,  which 
is  peculiar  to  the  Permean  system. 

IV.  Fossil  Animals. — One  hundred  and  sixty-six  species  are 

*  Red-dead-lier,  because  of  a  red  color,  dead  or  worthless,  not  containing 
metals,  and  underlying  the  metalliferous  strata. 

What  is  said  of  the  name  and  geographical  distribution  of  the  Permean 
rocks  ?  of  their  structure  ?  of  their  subdivisions  in  Germany  ?  of  the  fossil 
plants  ?  of  the  fossil  animals  ? 


FOSSIL    ANIMALS. 


255 


Fig.  159. 


known,  of  which  148  belong  exclusive- 
ly to  this  system ;  the  remaining  18 
have  been  continued  from  older  form- 
ations. Of  these  18,  ten  are  the  shells 
of  Brachiopods. 

1.  Radiata. — There  are  only  15  spe- 
cies of  corals,  and  these  are  mostly  rare 
The  Crinoideans  were  represented  by 
only  one  species. 

2.  Mollusca. — We  select  five  species 
of  shells  which  are  characteristic  of  this  system. 

Fig.  160. 


ODONTOPTERIS  STROGONOVI. 


a  a.  Terebratula  Schlotheimi.  c.  Productus  horrescens. 

b  b.  Spirifer  Blasii.  d.  Modiola  Pallasi. 

e.  Murchisonia  subangulata. 

3.  Articulata.  —  In  this  period  the  existing  genus,  Limulus 
(horse-foot),  was  introduced,  and  the  Trilobites,  which  had  flour- 
ished abundantly  during  nearly  all  the  older  epochs,  had  disap- 

peared. 

What  is  said  of  the  radiata?  of  the  articulata? 


256  CARBONIFEROUS    SYSTEM. 

4.  Fishes. — The  conditions  of  life  were  more  favorable  to  this 
class  of  animals  than  to  some  Dthers.  Forty-three  species  have 
been  found.  The  two  most  characteristic  genera  are  Palaeonis- 
cus  (Fig.  161)  and  Platysomus. 

Fig.  161. 


PAUEONISCUS. 

5.  Reptiles. — Some  lizard-like  reptiles  are  interesting,  as  the 
oldest  representatives  of  this  class  with  which  we  are  acquainted, 
with  the  exception  of  some  species,  which  are  known  by  their 
footprints  only,  in  the  carboniferous  system. 

SECTION  II.— CARBONIFEROUS  SYSTEM. 

I.  Geographical  Distribution. — This  system  is  widely  extend- 
ed in  both  hemispheres.  On  this  continent  it  furnishes  a  rich 
bituminous  coal-field  in  Nova  Scotia.  In  the  eastern  part  of 
Massachusetts  there  is  a  small  anthracite  coal-field. 

The  largest  explored  coal-field  in  the  world  has  its  northeast 
extremity  west  of  the  Delaware  River,  in  New  York,  and  ex- 
tends through  Pennsylvania  into  Ohio  westward,  and  to  Alaba- 
ma on  the  southwest.  It  covers  more  than  100,000  square  miles, 
and  contains  more  than  one  million  of  million  tons  of  bituminous 
coal.  A  much  less  extensive  but  rich  field  of  anthracite  coal  lies 
in  the  eastern  part  of  Pennsylvania,  east  of  the  Delaware  River. 
The  central  region  of  Michigan  constitutes  another  large  coal- 
field. Another  covers  most  of  Illinois,  the  southwest  part  of  In- 
diana, and  the  adjacent  part  of  Kentucky. 

What  is  said  of  the  fishes  ?  of  the  reptiles  ?  In  what  regions  in  North  Amer- 
ica does  the  carboniferous  system  occur  1  What  is  said  of  the  largest  coal- 
field? 


STRUCTURE    AND    POSITION.  257 

The  carboniferous  system  is  found  in  Vancouver  s  Island  and 
in  New  Mexico ;  and  in  South  America,  in  Chili. 

It  occurs  also  in  England,  Scotland,  Ireland,  Central  France, 
Spain,  Belgium,  Westphalia,  and  in  Russia,  from  the  White  Sea 
on  the  north  to  Kaluga  on  the  south.  It  is  found  in  Java,  in 
Borneo,  and  in  China. 

II.  Structure  and  Position. — Sandstones,  conglomerates,  and 
sV.ales,  alternating,  in  some  parts  of  the  series,  with  beds  of  coal, 
constitute  this  system.  In  some  districts,  calcareous  strata  occur ; 
but  they  are  much  less  common  in  the  Atlantic  States  of  North 
America  than  the  Western  States  or  in  Europe. 

The  accompanying  section,  Fig.  162,  exhibits  the  relations  of 
this  system  to  the  older  rocks  in  the  northeast  extremity  of  the 
great  Ohio  coal-field  in  the  northern  part  of  Pennsylvania. 

Fig.  162. 


Here  we  see  the  effects  of  the  extensive  denudation  which 
these  rocks  have  suffered.  Probably  the  contiguous  parts  of 
Pennsylvania  and  New  York  were  once  entirely  covered  with 
them.  Now  only  a  few  insulated  summits  remain.  Fig.  139 
(p.  242)  exhibits  the  relations  of  this  system  to  the  newer  rocks 
in  England. 

Fig.  163,  p.  258,  exhibits  details  of  structure  in  a  section  of 
the  coal  strata  on  Kenawha  River,  Ohio. 

In  what  other  countries  does  coal  occur  ?  What  is  the  structure  of  the 
rocks  ?  What  is  said  of  the  effects  of  denudation  ? 


258 


CARBONIFEROUS    SYSTEM. 


Fig.  163. 


Thickness 
feet. 


80.     Coarse  sandstone,  containing  fossil  trees. 


1.       Argillaceous  iron  ore. 

6.       Silicious  slate,  used  by  Indians,  for  arrow-heads. 

4.       Bituminous  coal. 


150.  Coarse  sandstone. 


4.       Bituminous  coal. 


200.  Argillaceous   sandstone,  containing  vegetable   im- 
pressions abundantly. 


If.  Coal. 

40.  Bituminous  shale,  with  sand. 

6.  Coal. 

60.  Compact  sandstone. 


The  continuity  of  coal  and  other  strata  is  often  interrupted 
by  dislocations,  of  which  usually  no  traces  appear  on  the  surface 

of  the  ground,  in 
consequence  of 
subsequent  denu- 
dation of  the  sur- 
face. Fiff.  164 


represents  a  sec 
tion  of  an  English 
coal-field.       The 
Describe  the  section  at  Kenawha  River ;  the  section  of  an  English  coal-field 


FOSSILS — PLANTS.  259 

strata  are  numbered  in  descending  order.  There  are  four  dif- 
ferent levels.  In  A  B  the  coal  X  is  900  feet  below  the  surface; 
in  B  C  it  is  within  200  feet  of  the  surface,  covered  by  No.  5 ;  in 
C  D  it  is  700  feet  below  ihe  surface,  and  No.  1  only  is  wanting ,' 
in  D  E  it  is  somewhat  higher  than  in  B  C. 

III.  Fossils. — 1.  Plants.  This  system  is  remarkable  for  con- 
taining not  only  a  vast  quantity  of  vegetable  matter  in  the  form 
of  coal,  but  also  for  the  great  number  and  variety  of  the  remains 
of  plants.  About  1000  species  have  been  described,  which  is 
rather  more  than  half  of  the  entire  number  found  in  a  fossil  state. 
This  is  the  more  remarkable,  since  only  a  few  species  have  been 
found  in  the  older  rocks.  It  is  also  remarkable  that  while  few 
animal  remains  have  been  found  in  the  coal  formation,  the  plants 
were  almost  wholly  of  families  which  were  not  adapted  for  the 
food  of  animals.  A  large  proportion  of  the  vegetation  of  this 
period  consisted  of  tree  ferns,  and  of  plants  intermediate  between 
the  coniferas  and  the  endogens. 

The  wide  distribution  of  the  species  is  worthy  of  notice.  Sev- 
eral have  been  found  to  be  identical  in  Europe  and  in  North 
America.  The  distribution  of  the  species  of  animals  was  also 
on  the  same  plan,  not  only  in  this  but  in  all  the  earlier  periods. 
It  has,  therefore,  been  inferred  that  the  climate  was  then  more 
uniform  over  the  earth's  surface  than  at  the  present  time. 

(1.)  Calamites  is  the  name  given  to  a  tribe  of  plants,  which  are 
sometimes  mistaken  by  the  ignorant  for  petrified  snakes.  Some 
botanists  have  supposed  them  to  have  been  a  kind  of  reeds  allied 
to  equisetum ;  but  a,s  they  had  a  true  bark,  according  to  Pro- 
fessor Lindley,  they  could  not  have  belonged  to  the  class  of  en- 
dogens. .They  were  branching  plants,  with  hollow  stems,  of  large 
size,  and  were  very  fragile.  They  are  often  found  much  com- 
pressed. The  surface  was  covered  with  deep  longitudinal  fur- 
rows, which  terminated  at  the  joints.  Some  have  been  found 
three  feet  in  diameter  and  thirty  to  forty  feet  long. 

It  is  very  rarely  that  the  stellate  sheaths  of  the  joints  are  found 

What  is  said  of  the  species  of  fossil  plants  ?  of  the  general  character  of  the 
plants  ?  of  their  distribution  ?  of  calamites  ? 


CARBONIFEROUS    SYSTEM. 


as  in  Fig.  165,  a,  of  Catamites  radiata  ;  or  that  the  remains  of 
roots  are  found,  as  in  I.     c  shows  the  curved  upper  extremity 
of  Calamites  approximata.     a  and  b  are  £,  and  c  |  natural  size. 
Fig.  166  (y1^  natural  size)  represents  a  calamite  from   Pi&- 166- 
Seekonk,  Massachusetts,  now  in  the  Museum  of  Am- 
herst  College.  jj 

Fig.  165. 


CAULOPTERIS. 


(2.)  Ferns. — The  carboniferous  period 
was  remarkable  for  the  great  number  and 
size  of  its  ferns.  Many  of  them  were  more 
analogous  to  the  tree«ferns,  which  now  in- 
habit the  torrid  zone,  than  to  any  which 
live  in  our  northern  temperate  zone.  The 
fronds  or  leaves  of  modern  tree-ferns  are 
often  ten  or  twelve  feet  long,  and  are  mi- 
nutely and  elegantly  subdivided. 

More  than  200  extinct  species  have 
been  found  in  the  carboniferous  system. 
The  stems  and  leaves  are  almost  invaria- 


What  is  said  of  the  general  character  of  the  ferns  ?  of  the  species  of  ferns  ? 


FOwSILS PLANTS. 


261 


oly  separate ;  and  since  the  parts  of  extinct  species  and  genera 
of  plants  can  not  be  reunited  with  the  same  accuracy  with  which 
the  comparative  anatomist  reconstructs  an  extinct  animal,  bot- 
anists have  been  obliged  to  give  different  names  to  the  leaves  and 
to  the  stems.  The  provisional  name  of  Caulopteris  has  there- 
fore been  given  to  the  stems  (Fig.  167). 

Fig.  168  represents  a  part  of  two  leaves  of  Pecoptcris  hngi- 
Jblia,  from  Rhode  Island  ;  Fig.  169  represents  a  leaf  and  part 
of  the  stem  of  Odontopteris  Brardii,  also  from  Rhode  Island. 

168  (PECOPTEBI3  LONGIFOLIA). 


Fig.  169    (ODONTOPTEEIS   BRARDH). 

Fig.  170. 


Fig.  171. 


PECOPTERIS  MANTELLI. 


NEUROPTERIS  FLEXUOSA. 


Fig.  17C  is  Pecopteris  Mantelli,  from  England  ;  and  Fig.  171  is 
Nf,uroptcris  flcxuosa,  also  from  England. 

(3.)  Lcpidodendron  (scaly  tree)  is  the  name  given  to  an  anom« 
What  is  said  of  the  Lepidodendron  ? 


262  CARBONIFEROUS    SYSTEM. 

alous  type  of  plants,  which  were  much  like  the  existing  club- 
mosses  (Lycopodiacese),  in  respect  of  texture,  surface  of  the  stem 
ramification,  and  foliage.  But  they  were  large  trees.  In  an 
English  coal  mine  one  specimen  was  found  which  was  forty 
feet  long,  and  at  the  base  thirteen  feet  in  diameter ;  at  the  sum- 
mit it  had  fifteen  or  twenty  branches.  Having  a  true  bark, 
they  could  not  have  belonged  to  the  same  class  with  our  Lyco- 
podiacese. In  the  arrangement  of  the  leaves  they  also  resembled 
coniferae. 

Fig.  172  shows  the  ramifications  of  a  Lepidodendron  and  the 
leaves  of  the  extremities.  This  specimen  was  found  in  the  coal 
shale  of  Newcastle,  England. 

Lepidostrobus  is  supposed  by  some  to  have  been  the  fruit  of 
the  Lepidodendron.  Fig.  173,  <z,  represents  the  rare  example  of 
a  young  fruit  at  the  end  of  a  branch.  Fig.  173,  b,  shows  the  form 
and  structure  of  the  ripe  fruit,  and  its  internal  axis. 

Halonia  regularis,  Fig.  173,  c,  from  Coalbrook  Dale,  England, 
had  a  remarkably  knotted  surface.  It  was  probably  allied  to 
the  Lepidodendron. 

(4.)  Sigillaria  and  Stigmaria. — These  were  once  supposed 
to  be  two  distinct  plants ;  but  it  is  now  well  known  that  the  for- 
mer is  the  stem  and  the  latter  the  root  of  a  large  tree.  Fig.  174 
represents  a  specimen  found  in  a  coal  mine  near  Liverpool,  En- 
gland, with  the  roots  proceeding  from  the  stem. 

In  coal  mines  the  roots  of  this  tree  are  found  abundantly  in  a 
deposit  of  clay,  which  invariably  underlies  the  coal,  and  is  there- 
fore called  underclay.  The  trunks  are  generally  found  in  a  hor- 
izontal position ;  but,  in  one  instance,  five  stems  were  found 
erect,  near  Manchester,  England,  where  they  have  been  secured 
in  their  position.  In  another  case,  a  group  of  forty  trees  was 
found,  standing  not  more  than  three  or  four  feet  apart.  The 
stems  vary  from  a  few  inches  to  five  feet  in  diameter,  and  five  to 
sixty  feet  in  length. 

What  is  said  of  the  Lepidostrobus  ?  of  the  character  of  Sigillaria  and  Stigk 
maria  ?  of  their  position  ? 


FOSSILS PLANTS. 

Fig .  174. 


263 


364 


CARBONIFEROUS    SYSTEM. 


plants  in  connection  with  it. 


.  176. 


Fig.  175  shows  the  scarred  surface  of  a  species  of  Sigillaria. 
Fig.  175.  a.  The  scars  left  on  the  bark  by 

the  fallen  petioles. 

b.  The  surface  beneath  the  bark, 
exposed  by  the  removal  of  a  part 
of  the  carbonized  bark. 

(5.)  Origin  of  Coal— (a.)  The 
vegetable  origin  of  coal  might  be 
inferred,  with  some  probability, 
from  the  great  abundance  of  fossil 
But  it  is  more  satisfactorily  de- 
monstrated from  the  microscopic  examination  of  the  structure  of 
pieces  of  coal.  The  most  convenient  method  is  to  take  a  piece 
of  partially-burned  anthracite  from  the  fire.  The  vegetable  cells, 
being  more  or  less  silicious,  retain  their  form  after  the  carbon  is 
partly  burned  away,  and  may  be  seen  with  a  microscope  on  the 
surface  of  the  specimen.  Fig.  176,  a,  represents  several  ducts 

in  superimposed  layers ;  b 
shows  two  ducts  more  high- 
ly magnified.     The  white 
spaces  are  the  patches  of 
silica,  and  the  black  lines 
are  the  unburned  carbon. 
From    such    observations, 
Professor  Bailey,  of  West 
Point,  infers  (1.)  that  the 
material  of  coal  could  nev- 
er have  been  reduced  to  q 
homogeneous    pulp ;     but 
(2.)  that  coal  is  composed 
of  thin  layers  of  vegetable  bodies  confusedly  intermingled.    This 
method  of  examination  is  less  applicable  to  soft  coal,  on  account 
of  the  partial  fusion,  and  the  swelling  caused  by  the  bitumen, 
But  other  methods  have  detected  in  it  a  vegetable  structure. 
(b.)  Different  theories  have  been  proposed  to  explain  the  man- 
\/hat  is  said  of  the  origin  of  coal  ?  of  its  structure  ? 


FOSSILS PLANTS. 


265 


ner  in  which  the  strata  of  coal  may  have  been  preserved.  In 
some  places,  their  alteration,  in  a  thick  series,  with  strata  which 
contain  marine  shells,  and  with  others  which  contain  fresh  water 
shells,  is  thought  to  indicate  successive  rise  above  and  subsidence 
beneath  the  waters  of  the  ocean.  The  subsidence  accounts  suf- 
ficiently for  the  covering  and  subsequent  preservation  of  the  veg 
etable  matter.  In  other  cases,  perhaps  more  frequently,  the  veg- 
etable matter  may  have  been  carried  down  large  rivers  into  the 
sea,  and  becoming  water-logged,  have  sunk  to  the  bottom.  But 
it  has  been  said  that  this  could  not  have  been  the  origin  of  those 
coal-fields  in  which  trunks  of  Sigillaria  are  found  erect ;  although 
some  stems  might  have  this  position  from  the  settling  of  the  roots, 
like  snags  in  rivers. 

2.  Animals. — The  number  of  species  known  is  not  far  from  one 
thousand.  Most  of  them  are  shells.  A  large  majority  do  not 
occur  in  the  proper  coal  formation,  but  in  the  other  members 
of  the  system. 

(1.)  Of  Radiated  animals  the  remains  of  fifteen  to  twenty  spe- 
cies have  been  found,  very  few  of  which  have  been  found  in  the 
other  systems.  Fig.  177  shows  the  corals,  encrinites,  &c.,  which 

Fig.  177. 


t»re  exposed  on  a  weather-worn  slab  of  the  carboniferous  lime* 

stone  of  Iowa. ^ 

What  is  said  of  the  theories  of  th«  uroservation  of  the  coal?  of  the  specie* 
of  fossil  animals  ?  of  the  Radiata  ? 

11 


266 


CARBONIFEROUS    SYSTEM. 


Fig.  179. 


Actinocrinites  triakonta-dac- 
tylus. 


Fig.  180. 


Fig.  173  Fig.  178  shows  the  body  of  the  thirty- 

fingered  Actinocrjukes  of  the  mountain 
limestone  of  Europe.  Each  of  the  five 
branches  was  subdivided 
into  two,  and  each  of  these 
into  three.  The  figure 
shows  the  base  of  the 
branches. 

Fig.  179  is  Pentremites 
inflatus,  from  the  same  for- 
mation. Both  of  these  animals  had  five-sided  pe- 
duncles. 

(2.)   Molluscs.— The   Foramin- 
ifera,  a  class  of  molluscs  usually 
of  microscopic  size,  and  of  an  in- 
ferior grade  of  organization  (see 
page   197),  were  represented  by 
several  species  during  this  period. 
The  class  of  Brachiopods  was  most 
abundantly  represented.  The  shell 
of  Productus  spinulosus,  Fig.  180, 
was  remarkable  for  its  long  spines. 
There  were  thirty  species  of  the 
genus  Productus.     Productus  gi- 
ganteus  was  a  very  large  Euro- 
pean species,  five  inches  long  and 
four  inches  high.    Spirifer,  anoth- 
er   genus    of  Brachio- 
pods, was    represented 
by  25  species.    Fig.  181 
shows  the  parts  of  Spi 
rifer  striatus.    «,  the  ex 
ternal  surface,   b,  the  in- 
Spirifer  striatus.  terior,  showing  the  spi 

ral  coil,     c,  part  of  the  coil  detached. 

What  is  said  of  the  Foraminifera  ?  of  the  Brachiopods  ? 


Productus  spinulosus. 
Fig.  181. 


FOSSILS— PLANTS. 


26? 


The  Gasteropods  were  represented  by  several  geneia,  many 
182  of  which  now  exist,  while  others 

became  extinct  in  this  period.  Of 
the  latter  number  was  Euomphalus, 
which  had  been  introduced  in  the 
earliest  Palaeozoic  times.  Fig-  182 
represents  a  beautiful  species,  E. 
equalis,  found  in  Russia.  Although 
a  Gasteropod,  the  animal  had  a 
chambered  shell,  for  it  formed  im 
perforate  partitions  in  Fig,  133. 
its  successive  retreats  from  the  older  portions  of  the 
shell.  Natica  Omaliana,  Fig.  183,  has  been  found 
in  Russia  and  in  Belgium,  and  belonged  to  a  genus 
which  was  introduced  in  the  older  Palaeozoic  periods,  and  is  now 
abundantly  represented  in  all  climates. 

Of  the  Cephalopods,  Goniatites  is  a  genus  which  became  ex- 
tinct  in  this  period.  Fig.  184 
represents  a  remarkable  species, 
G.  Jossae,  which  is  found  in  Rus- 
sia. The  lines  of  the  junction 
of  the  partitions  with  the  ex- 
terior shell  were  very  tortuous. 
Orthoceratites  is  another  Ce- 
phalopod  genus,  which  had  been 
introduced  in  the  earliest  Palaeo- 
zoic periods,  and  became  extinct  in  this  epoch.  Fig. 
185  shows  the  internal  structure  of  a  species.  The 
genus  Ammonites  (see  p.  219),  although  of  early  in- 
troduction, did  not  become  extinct  until  the  last  of  the 
Mesozoic  periods.  It  was  represented  in  this  period  by  several 
species.  Many  of  them  occur  in  the  Western  States. 

Fresh  water  species  of  the  existing  genera  Unio  and  Anodonta 
occur  in  the  coal  formation. 

Although  none  of  the  species  of  this  epoch  survived  the  change 
What  is  said  of  the  Gasteropods  ?  of  the  Cephalopods  ? 


268 


CARBONIFEROUS    SYSTEM. 


from  Palaeozoic  to  Mesozoic  times, 
yet  23  genera  of  the  shells  have  con- 
tinued to  the  present  time.  They  be- 
long mostly  to  the  Acephala  and  Gas- 
teropoda. 

(3.)  Fishes. — The  fishes  of  this  pe- 
riod have  been  very  abundantly  pre- 
served. Not  less  than  150  species 
have  been  found.  Megalichthys  and 
Holoptychus  were  gigantic  sauroid 
fishes,  whose  remains  are  found  with 
plants  and  crustaceans,  which  indi- 
cate a  lacustrine  or  estuary  formation 
Fig.  186  represents  a  tooth  of  one  of 
these  fishes  of  the  natural  size.  Their 
teeth  are  larger  than  those  of  any 
other  fishes  which  have  conical  teeth. 
(4.)  Reptiles.  —  In  the  carbonifer- 
ous rocks  of  Nova  Scotia,  the  foot- 
prints of  a  reptile  have  been  found. 
In  those  of  Pennsylvania,  the  tracks 
of  a  reptile  were  discovered  by  Dr. 

HOLOPTYCHUS  HiBBERTi.  A.  T.  King,  who  named  the  animal 
Thenaropus  heterodactylus,  Fig.  187.  The  hind  foot  resembles  a 
iuman  hand.  The  reptile  may  have  been  a  batrachian. 

Fig.  187. 


THENAROPUS    HETERODACTYLUS,  KING. 


In  1848,  Dr.  Isaac  Lea,  of  Philadelphia,  discovered  near 
Pottsville,  in  Pennsylvania,  certain  reptilian  tracks.  There  are 
six  double  impressions  13  inches  apart.  The  animal  which  made 
them  has  been  named  by  Dr.  Lea  Sauropus  primcevus.  Fig  188 

What  is  said  of  the  genera  of  the  shells  of  this  period  ?  of  the  fishes  ?  of  the 
reptiles?  of  the  tracks  discovered  by  Dr.  Leaf 


CLIMATE    AND    GEOGRAPHY. 


269 


represents  one  pair  of  tracks  about f  of  the  natuial  size.  Dr 
Lea  refers  their  position  to  the  Devo 
nian  system,  but  Professor  H.  D.  Rog- 
ers places  them  above  the  middle  of  the 
carboniferous  system,  yet  much  below 
the  tracks  which  were  discovered  by 
Dr.  King.  They  are,  therefore,  very 
interesting  as  the  oldest  remains  yet 
known  of  any  reptilian  or  of  any  air- 
breathing  animal. 

IV.  Climate  and  Geography. — From 
the  vast  quantity  of  the  vegetable  mat- 
ter, and  from  the  remains  of  fresh  water 
shells,  it  may  be  inferred  that  there  was  no  inconsiderable  amount 
of  dry  land  during  this  period.  From  the  character  of  the  plants, 
it  has  been  inferred,  also,  that  the  land  must  have  been  low,  and 
perhaps  consisted  to  a  large  extent  of  islands.  If,  however,  the 
beds  of  coal  originated  in  vegetable  matter  brought  down  by 
rivers,  there  must  have  been  large  rivers,  and  consequently  large 
continents. 

Professor  H.  D.  Rogers  finds  that  the  coal-beds  of  Eastern 
Pennsylvania  were  derived  from  a  continent  lying  to  the  east- 
ward, and  occupying  more  or  less  of  the  space  which  is  now  filled 
by  the  Atlantic,  while  the  ocean  of  this  period  occupied  the  re- 
gion westward,  and  covered  most  of  the  continent  of  North 
America.  The  gradual  retreat  eastward  of  the  Atlantic  conti- 
nent is  indicated  by  the  greater  extension  eastward  of  each  suc- 
cessive coal-bed  as  we  ascend  the  series.  The  retreat  eastward 
of  this  continent  must  have  been  due  to  its  subsidence  beneath 
the  ocean,  as  is  obvious  also  from  the  thickness  of  the  series  of 
strata  which  intervene  between  the  coal-beds. 

It  has  been  generally  inferred,  from  the  character  of  the  plants, 
that  the  climate  was  tropical ;  and  some  have  supposed  that  it  waf 
ultra-tropical.  Most  of  the  existing  tree-ferns  and  other  plantr 

What  is  said  of  the  extent  of  dry  land  ?  of  the  continent  occupying  the  are 
of  the  Atlantic  ?  of  the  climate  ? 


;HO  DEVONIAN    SYSTEM. 

which  resemble  those  of  the  carboniferous  epoch  are  tropical. 
Yet  the  abundance  of  a  similar  vegetation  in  New  Zealand,  and 
the  difference  of  the  species  and  genera  of  that  period  from  those 
which  now  exist,  will  not  permit  us  to  infer  confidently  that  the 
mean  temperature  of  the  earth's  surface  was  much  higher  than 
at  present.  But  the  temperate  and  northern  regions  may  have 
been  warmer,  and  it  is  almost  certain  that  a  very  uniform  climate 
prevailed  over  large  areas. 

During  this  period  a  great  quantity  of  carbon  was  buried  be- 
tween the  sedimentary  strata.  But  since  the  carbon  was  of  veg- 
etable origin,  and  since  plants  derive  their  carbon  from  the  car- 
bonic acid  gas  in  the  atmosphere,  it  has  been  inferred  that,  up 
to  this  period,  the  atmosphere  had  been  loaded  with  a  much 
greater  quantity  of  carbonic  acid  than  it  has  since  contained. 
The  total  amount  of  coal  in  the  world  has  been  estimated  at 
5,000,000,000,000  of  tons.  The  quantity  of  carbon  now  in  the 
carbonic  acid  of  the  atmosphere  is  850,000,000,000  tons.  Hence, 
previous  to  the  coal  vegetation,  the  atmosphere  must  have  con- 
tained six  times  its  present  amount.  Such  an  atmosphere,  with 
a  moist  temperature,  and  a  uniformly  warm  climate,  would  have 
fulfilled  the  conditions  most  favorable  to  an  exuberant  vegetation. 

SECTION  TIL-DEVONIAN  SYSTEM— OLD  RED  SANDSTONE. 

I.  Geographical  Distribution. — In  the  United  States  this  sys- 
tem has  its  principal  development  in  a  region  which  includes  the 
Catskill  Mountains  of  New  York  on  the  northeast,  extending  to 
the  anthracite  coal  district  of  Pennsylvania  on  the  south,  while 
it  is  prolonged  westward,  in  a  narrow  belt,  around  the  great  bi- 
tuminous coal-field  in  Western  Pennsylvania.  Farther  to  the 
southwest,  it  extends  in  narrow  belts  along  the  Alleghany  Mount- 
ains. But  some  geologists  do  not  regard  these  rock  ?  as  belong- 
ing to  the  Devonian  system. 

In  Russia,  in  Europe,  this  system  covers  a  vast  region  150,000 
square  miles  in  extent.  Occupying  most  of  the  western  part  of 

What  is  said  of  the  atmosphere  ?  of  the  distribution  of  Devonian  rocks  in 
the  United  States?  in  Europe? 


FOSSILS.  271 

Russia,  it  extends  to  the  northeast  in  one  long  arm  beyond  Arch- 
angel, while  another  arm  extends  to  the  southeast  beyond  the 
River  Don.  It  also  occurs  along  the  western  flanks  of  the  Ural 
Mountains.  In  Western  Europe,  this  system  is  well  developed 
in  the  Rhenish  provinces ;  it  has  been  most  carefully  studied  in 
the  southwest  part  of  England,  and  in  Scotland,  where  it  is  10,000 
feet  thick.  It  occurs  also  in  Ireland,  France,  and  Spain. 

II.  Structure  and,  Position. — The  strata  of  the  Devonian  system 
are  composed  of  dark  red  sandstones  and  conglomerates  in  the 
upper  part,  and  of  calcareous  slates  and  flagging  stones  in  the 
lower  part,  in  England.     In  New  York  they  consist  of  red, 
brown,  gray,  and  green  sandstones,  and  conglomerates,  and  of 
fissile  sandstones  and  slates  of  the  same  colors. 

Fig.  162  (p.  257),  and  Fig.  198  (p.  275)  exhibit  the  position  of 
this  system  in  New  York. 

III.  Fossils. — More  than  seven  hundred  species  have  been 
found,  of  which  a  majority  are  shells.    Fishes  are  also  preserved 
in  great  numbers. 

1.   Plants. — Very  few  species  remain,  and  these  are  said  to 
have  been  mostly  marine. 

2-  Animals. — (1.)  Radiata.  Corals 
and  Crinoideans  were  very  abundant 
during  this  period. 

Fig.  189  is  Favosites  polymorphus, 
a  coral  of  this  period. 
(2.)  Articulata. — The  existing  genus  Serpula  makes  its  first 
appearance  in  these  strata.  These  animals  are  marine  worms, 
which  are  covered  by  a  solid  calcareous  secretion.  Their  tubes 
are  irregularly  twisted,  and  are  joined  in  large  masses  or  attached 
to  other  marine  bodies.  Of  crustaceans,  trilobites  occur  much 
more  rarely  than  in  the  older  Paleeozoic  rocks.  Brontes  flabcl- 
lifcr  was  a  crustacean  of  the  order  Macroura,  somewhat  like  a 
lobster,  but  was  four  feet  long.  Fig.  190,  page  272,  represents 
the  tail. 

What  Is  said  of  their  structure  ?  of  their  position  ?  of  the  number  of  fossil 
species?  of  the  plants?  of  the  radiata  ?  ofserpula?  of  the  Crustaceans? 


272 


DEVONIAN    SYSTEM. 


(3.)  Molluscs. — Of  the  Brachiopods,  the  existing  genus  Tere~ 
bratula  was  abundantly  represented.  The  genus  Spirifer  was 
also  well  represented.  The  genus  Strigocephalus  was  introduced 
during  this  period.  Fig.  191  is  S.  Bartini. 

Fig.  190. 

Fig.lSL. 


Strigocephalus  Bartini. 

Of  the  Acephala  there  were  many  species.  Fig.  192  is  Cy- 
pricardites  angustata,  from  tho  Catskill  region,  in  New  York. 
Murchisonia  intermedia.  Fig.  193,  is  an  example  of  the  Gastero- 

Fig.  192.  Fig.  193. 


Clymenia  insequistriata. 


pods  of  this  period.  Of  the  Ce- 
phalopods,  the  genus  Clymenia, 
Fig.  194:,  which  had  the  siphun- 
cle  along  the  inner  margin  of 
the  partitions,  was  introduced 
during  this  period.  Thirty-five 
species  of  this  genus  have  been 
found  at  one  locality  in  Bavaria. 
This  number  embraces  nearly 
all  the  known  species. 

(4.)  Fishes. — This  period  was 
remarkable  for  the  number  and 
extraordinary  character  of  the 
fishes.  Seventy-five  species  have 


What  is  said  of  the  Brachiopods?  of  the  Acephala?  of  Clymenia?  of  th« 
fishes? 


FOSSILS. 


273 


been  found.  They  occur  chiefly  in  the  sandstones  of  Scotland 
and  Russia,  while,  in  the  same  kind  of  rocks,  shells  are  rare  in 
both  of  these  countries. 

In  one  family  of  fishes  the  head  was  greatly  developed.    Such 

Fig.  195. 


was  Cephalaspis  Lyellis,  Fig.  195.     PterichtJiys  cornutus,  Fig. 
196,  was  remarkable  for  its  wing-like  appendages.     In  other  re- 

196. 


spects,  the  Coccostcus  oblongus  was  allied  to  it,  but  had  the  tail 
needle-shaped,  and  much  longer. 

One  of  the  most  extraordinary  genera  was  Holoptychus.  Il 
fiad  very  large,  stout,  enameled  scales,  which  constituted  a  de- 
fensive armor  of  great  strength.  Some  of  the  scales  were  nearly 

Fig.  197. 


What  is  said  of  Cephalaspis  ?  of  Pterichthys  ?  of  Holoptychus  ? 

M2 


274  SILURIAN    SYSTEM. 

three  inches  long  and  two  and  a  half  inches  wide.  Fig.  197 
page  273,  represents  a  specimen  of  HoloptycJms  nobilissimus^ 
which  is  two  feet  four  inches  long  and  twelve  inches  wide.  The 
animal  appears  to  have  sunk  quietly,  after  death,  to  the  bottom 
of  the  sea,  lying  on  its  back  in  the  sandstone  of  Scotland.  Some 
fish-bones  in  the  Devonian  strata  of  Dorpat,  Russia,  must  have 
belonged  to  fishes  30  or  40  feet  long.  One  bone  is  three  feet  in 
length.  Scales  of  Holoptychus  are  common,  also,  in  the  old  red 
sandstone  of  New  York. 

SECTION  IV.— SILURIAN  SYSTEM. 

I.  Geographical  Distribution. — This  system  occurs  in  the  basin 
of  Hudson's  Bay,  in  the  valley  of  the  River  St.  Lawrence,  and  in 
the  valley  of  Lake  Champlain.     In  the  western  part  of  New 

rork,  it  is  most  fully  developed  with  a  great  number  of  subdivi- 
sions, regularly  superimposed,  and  with  outcrops  in  favorable  con- 
ditions for  examination.  In  a  southwest  direction  it  extends 
along  the  Alleghany  Mountains,  which  are  mostly  constituted  of 
its  members.  In  the  "Western  States,  the  upper  part  of  the  sys- 
tem shares  most  of  the  surface  with  the  carboniferous  system. 

In  the  Northern  States,  the  Silurian  system  exists  in  a  highly 
metamorphic  condition,  having  been  changed  into  crystalline 
rocks. 

This  system  received  its  name  from  the  place  where  it  was 
first  successfully  investigated,  the  western  part  of  England,  which 
was  anciently  inhabited  by  a  tribe  called  the  Silures.  These 
rocks  occur  also  in  Belgium,  Germany,  Norway,  and  Sweden. 
In  Russia,  they  occupy  a  region  around  St.  Petersburg,  and  are 
found  in  the  Ural  Mountains  in  a  metamorphic  condition.  It  is 
rendered  probable,  by  fossils  which  have  been  collected  by  trav- 
elers, that  the  Silurian  system  exists  in  Terra  del  Fuego,  in  South 
Africa,  and  in  New  Holland. 

II.  Structure  and  Position. — A  great  variety  of  rocks  is  com- 

What  is  said  of  the  distribution  of  the  Silurian  system  in  North  America  ? 
of  its  condition  in  the  Northern  States?  of  its  name?  of  its  distribution  in  Eu- 
rope? of  its  structure  ? 


STRUCTURE    AND    POSITION. 


275 


prised  in  this  system.  Hard  sandstones,  fine  slates,  and  flagging 
stones  constitute  a  large  part.  Conglomerates  are  less  common, 
oome  of  the  formations  are  partly  calcareous,  and  others  consist 
chiefly  of  limestone,  and  furnish  excellent  marble.  It  is  an  ex- 
traordinary fact  that,  in  the  vicinity  of  St.  Petersburg,  this  most 
ancient  system  contains  beds  of  unconsolidated  clay. 

Fig.  198  exhibits  the  position  of  this  system  in  a  section  ex- 
tending from  the  north  side  of  Lake  Ontario  across  New  York 
into  Pennsylvania.  (See  Report  by  Professor  Hall.) 

Fig.  198. 


G        H 

NEW-YORK    SYSTEM. 


1.  A. 

2.  B. 

3.  C. 

4.  D. 

5.  E. 

6.  F. 
a. 

7.  G. 

8.  H. 


9    I. 


Primary  or  metamorphic  rocks. 

Potsdam  sandstone. 

Calciferous  sandrock. 

Black  River  limestone. 

Trenton  limestone. 

Utica  slate. 

Lake  Ontario. 

Hudson  River  group. 

Gray    sandstone    and    Oneida 

conglomerate. 
Medina  sandstone. 


10.  K.  Clinton  group. 

11.  L /.  Niagara  group. 

12.  M.  Onondaga  salt  group. 

13.  N.  Helderberg  series. 

14.  O.  Hamilton  group. 

15.  e.    Tully  limestone. 

16.  P.  Portage  group. 

17.  R.  Chemung  group. 

18.  S.  Old  Red  or  Devonian  system. 

19.  T.  Conglomerate  of  the  carbonifer- 

ous system. 


Fig.  199  exhibits  the  order  of  the  Silurian  rocks  in  England. 

Fig.  199. 


ORDER    OF    SUPERPOSITION    OF    THE    SILURIAN   ROCKS. 


7.  Upper  Ludlow  shale.  } 

6.  Aymestry,  or  Ludlow  limestone.  >  Ludlow  series. 

5.  Lower  Ludlow  shale.  ) 

4.  Wenlock  limestone.  \\HT     \     ^ 

3.  Wenlock  shale.  J  Wenlock  series. 

2.  Caradoc  sandstone. 

1.  Llandeilo  flags.  5 " ' 


Upper  Silurian. 


.  Lower  Silurian. 


Fig.  200,  page  276,  exhibits  the  order  of  these  rocks  in  the 
territory  of  Christiana,  in  Norway. 


Describe  the  section  across  New  York ;  the  section  in  England. 


276 


SILURIAN    SYSTEM. 


Fig.  200. 


t.  Trap   &c.  ?£r     ti 

p,  Porphyry.  $ 

e    Old  red  sandstone.     Devonian. 


Calcareous  flagstones,  &c.         ?  TT««QW  Q-I  ,™™ 
Coralline  limestone  and  shale.  \  UPPer  Sllunan 


Pentamerus  limestone. 
Schists,  flags,  &c. 
Gneiss. 


Lower  Silurian. 


Ill,  Subdivisions  of  the  Silurian  System. — On  account  of  the 
number  of  regular  formations,  each  characterized  by  some  pecul- 
iar fossils,  while  other  fossil  species  extend  through  and  charac- 
terize entire  series  of  successive  formations,  it  is  practicable,  in 
most  countries,  to  make  convenient  subdivisions  of  this  system. 
In  New  York  it  has  been  divided  into  four  divisions.  They  are, 

1.  Erie  Division ;  R  to  O  in  Fig.  198. 

2.  Helderberg  Division ;  N.  to  M. 

3.  Ontario  Division ;  I  to  I. 

4.  Champlain  Division ;  H  to  B. 

The  first  of  these  divisions,  perhaps,  includes  in  its  upper  part 
some  strata  of  Devonian  age,  the  limit  between  the  two  systems 
not  being  clearly  defined  in  New  York. 

If  the  same  subdivisions  could  be  identified  in  distant  coun- 
tries, they  might  be  regarded  as  distinct  systems.  But  they  are 
not  persistent  over  large  areas.  In  the  Silurian  districts  of  the 
Western  States  some  of  the  New  York  formations  are  wanting, 
while  a  few  others  are  more  fully  developed.  This  may  be  seen 

Fig.  201. 


c          d       e 

a.  Coralline  beds.         )      Cliff" 

b.  Lead-bearing  beds.  $  limestone. 
e.  Blue  fossiliferous  limestone. 


d.  Buff-colored  stratum. 

e  e  e.  Red  and  white  sandstone. 

//.  Lower  magnesian  limestone. 


Describe  the  section  in  Norway.    What  is  said  of  the  subdivisions  1     Why 
are  they  not  distinct  systems  1 


FOSSILS.  277 

in  the  preceding  section  of  the  Silurian  rocks  of  Iowa,  Fig  201, 
from  Mr.  D.  D.  Owen's  Report. 

The  cliff  limestone  is  so  called  on  account  of  the  great  num- 
ber of  cliffs  composed  of  this  rock.  The  cliffs  have  resulted  from 
denudations  of  the  surface.  Its  upper  beds  abound  in  corals  and 
shells,  and  the  lower  part  constitutes  the  great  lead  region. 

In  Figs.  199  and  200  we  have  seen  the  subdivisions  of  the 
systeir.  in  England  and  in  Norway.  The  simple  division  into 
Upper  and  Lower  Silurian  may  be  applied  in"  most  countries 
where  these  rocks  occur. 

IV.  Fossils. — Very  few  species  of  plants  or  of  fishes  have 
been  found.  Except  fishes  and  a  chelonian  (fresh-water  tortoise), 
all  the  vertebrated  classes  are  wanting.  Several  Crustacea  oc- 
cur, and  the  family  of  trilobites  was  more  fully  represented  in  this 
than  in  any  other  period.  The  crinoideans  and  corals  were  also 
well  represented.  But  a  large  majority  of  the  fossils  are  shells. 

More  than  one  thousand  species  of  Silurian  fossils  are  known. 
Professor  Hall  has  described  three  hundred  and  eighty-one  spe- 
cies belonging  to  the  Champlain  division,  and  three  hundred  and 
forty-one  belonging  to  the  Ontario  division,  within  the  limits  of 
New  York. 

1.  Radiata. — (1.)  Corals.  One  of  the  most  beautiful  of  the 
Silurian  fossils  is  the  chain  coral,  Catenipora  escharoides.  Fig. 
203,  page  279,  represents  a  specimen  from  Iowa,  from  the  Uppei 
Silurian,  or  cliff  limestone.*  The  same  formation  also  contains 
several  other  species  and  genera  of  corals. 

Fig.  202,  I,  page  278,  represents  a  solid  coral,  Favistella  stel- 
lata,  from  the  Hudson  River  group  of  New  York,  n  and  p  rep- 
resent other  solid  corals :  n  is  Stictopora  fenestrata,  from  the 
Chazy  limestone  of  New  York ;  and  p  is  CJiatetes  Lycoperdon, 
from  the  Trenton  limestone  of  New  York.  In  Fig.  207  (p.  281), 
;  and  I  also  represent  solid  corals  :  j  is  a  species  of  Cyathophyl- 
lum,  from  the  Hamilton  group  in  New  York;  and  I  is  Astrcea 
rugosa,  from  the  Onondaga  limestone  of  New  York. 

Describe  the  section  in  Iowa.  What  is  said  of  the  kinds  of  fossils  ?  of  their 
onmber?  of  the  chain  coral  ?  Mention  some  examples  of  solid  corals. 


878 


SYSTEM. 


STMJRIAN    FOSSILS    OP    NEW    YORK 


CRINOIDEANS. 
Ttg.  203. 


279 


204. 


Fig.  202,  b,  represents  the  Tentaculitcs  ornatus,  from  the  Wa- 
ter Lime  group  of  New  York.  It  is  doubtful  whether  this  genus 
was  more  nearly  allied  to  corals  or  to  crinoideans. 

(2.)  Graptolites  were  probably  zoophytes.  Their  character 
has  been  much  discussed,  and  it  is  yet  uncertain  to  what  family 
in  this  class  of  animals  they  should  be  referred.  Some  have  sup- 
posed them  to  have  resembled  the  sea-pen.  Pennatula.  They 
are  very  common  in  some  argillo-calcareous  slates  (Fig.  202,  k). 
(3.)  Crinoideans.  —  The  following  figures  exhibit  some  of  the 
Silurian  types  of  this  elegant  family  of  star- 
fishes. Fig.  204  is  a  basal  view  of  the  body 
of  Platycrinus  discoidcus,  the  peduncle  hav- 
ing been  attached  to  the  central  piece  ;  the 
ramifying  arms  were  jointed  to  the  side- 
pieces.  This  species  is  from  Iowa. 

Fig.  202,  f,  represents  the  body  and  part 
of  the  arms  of  Hypantkocrinites  caslatus,from 
Lockport,  in  New  York,     q  represents  the  body,  arms,  and  a  part 
of  the  stem  of  Schizocrinus  nodosus,  from  the  Trenton  limestone 
at  Glenn's  Falls,  New  York.     Fig.  207,  g,  represents  all  the 
What  is  said  of  Graptolites?     Mention  some  examples  of  Crinoideans 


280  SILURIAN    SYSTEM. 

parts  of  Cyathocrinus  ornatissimus,  from  the  Poitage  group,  at 
Portland,  in  New  York.  Fig.  202,  c,  represents  the  body  of 
Caryocrinus  ornatus.  from  the  Niagara  group,  in  New  York. 

2.  Articulata. — The  crustaceans  were  represented  chiefly  by 
the  family  of  trilobites.     These  animals  were  divided  length- 
wise into  three  lobes,  and  transversely  into  numerous  segments. 
They  were    able  to  roll  themselves  up,  like   the  wood-louse. 
Many  were  entombed,  and  are  now  found  in  this  condition,  as 
represented  in  Fig.  205,  Calymene  Fischeri,  from  Russia.     Their 

Fig >2o5.  eyes  were   prominent  and  compound, 

consisting  of  many  tubes,  which  were 
less  numerous  and  larger  than  those 
which  we  see  in  the  compound  eyes  of 
insects  (Fig.  207,  k  Jt).  Although  mul- 
titudes of  specimens  have  been  careful- 
ly examined,  no  legs  have  been  discov- 
ered. Probably  they  had  small  and  fra- 
gile legs,  which  were  not  much  used  for 
locomotion.  Fig.  207,  k,  represents  Calymene  bufo,  from  the 
Hamilton  group,  in  New  York  :  this  specimen  is  partially  coiled. 

3.  Mollusca. — The  class  "Brachiopo da  had  its  greatest  develop- 
ment in  the  Silurian  periods.    Fig.  202,  e,  represents  Detliyris  de 
cemplicata,  from  the  Niagara  group,  at  Lockport,  in  New  York 
Fig.  202,  h,  is  Strophomena  striata,  from  the  same  locality,     i  is 

Fig.  206.  probably  OrtMsflabdlulum,  also  from 

Lockport.  Fig.  207,  a,  represents 
Atrypa  Jiystrix,  from  the  Chemung 
group,  at  Bath,  in  New  York,  b  rep- 
resents Delthyris  acuminata,from  the 
Chemung  group,  at  Ithaca,  in  New 
York,  f  is  Strophomena  sctigera, 
from  the  Marcellus  shale,  at  Avon, 
in  New  York.  Fig.  206  is  a  Euro- 
Pentamerus  Knightii.  pean  species,  Pentamerus  KnigTitii. 

What  is  said  of  the  structure  of  Trilobites?     Mention  some  examples  of 
Brachiopoda. 


MOLLUSCA. 


281 


BILUItlAU    FOSSIt  S    OP    NEW   TORf 


282 


SILURIAN    SYSTEM. 


Fig.  207,  c,  represents  Ortliis  interlineata,  from  the  Chemung 
group,  of  New  York.  Fig.  202,  m,  represents  Lingula  antiqua^ 
of  the  Potsdam  sandstone,  in  New  York.  This  is  the  oldest  of 
the  fbssiliferous  rocks ;  yet  the  same  genus  inhabits  the  tropical 
seas  of  the  present  time. 

Although  the  Acephala  are  now  far  more  numerous  than  the 
Brachiopoda,  yet  in  the  Silurian  periods  they  were  less  abun- 
dant. Fig.  202,  j,  represents  a  species  of  a  genus  long  since  ex- 
tinct, Pterinea  carinata,  from  the  Hudson  River  group,  in  New 
York.  Fig.  207,  d,  is  Avicula  spinigera,  from  the  Chemung 
group,  at  Painted  Post,  in  New  York.  This  extinct  species  be- 
longs to  the  existing  genus,  which  includes  the  pearl  oysters,  c 
represents  an  extinct  species  of  the  existing  genus  of  scallop 
shells,  Pecten  cancellatus,  from  the  Chemung  group,  at  Phillips- 
burgh,  in  New  York,  i  represents  Cypricardia  truncata,  from 
the  Hamilton  group,  at  Cayuga  Lake,  in  New  York. 

The  Gasteropoda,  now  by  far  the  most  numerous  of  all  the 
classes  of  mollusca,  were  also  rare.  Fig.  202,  a,  represents  the 
EuompJialus  profundus,  from  the  Pentamerus  limestone,  in  New 
York,  g  is  the  Bellerophon  bilobatus,  from  the  Trenton  lime- 
stone, in  New  York. 

The  CepJialopoda,  now  extremely  rare,  were  common,  and 
were  represented  by  a 
great  variety  of  gene- 
ric forms.  Fig.  202, 
d,  is  Cornulites  arcua- 
tus,  from  the  Niagara 
group,  in  New  York. 
Fig.  208  represents  a 
remarkable  shell,  Litu- 
ites  Ordini,  from  the 
Silurian  rocks  of  Rus- 
sia. Fig.  207,  h,  rep- 
resents a  remarkably 


Fig.  208. 


Mention  some  examples  of  Acephala ;  of  Gasteropoda ;  of  Cephalopoda. 


CUMBRIAN    AND    CAMBRIAN    SERIES.  283 

slender,  chambered  shell,  Orthoceras  aciculum,  from  the  Portage 
group,  at  Cashaqua  Creek,  in  New  York. 

4.  Fishes  and  Reptiles. — Fragments  of  eight  or  ten  species  of 
fishes  have  been  found,  and  the  tracks  of  at  least  one  reptile 
have  been  discovered  in  Canada  by  Mr.  Logan. 

5.  Plants  — The  fossil  represented  in  Fig.  202,  o,  is  supposed 
to  have  been  a  marine  plant,  and  has  been  called  Scolitkus  line- 
aris.     It  is  found  in  the  Potsdam  sandstone,  in  the  valley  of 
Lake  Champlain. 

V.  Climate  and  Geography. — The  farther  we  recede  from  the 
present  time  in  the  history  of  the  earth's  surface,  the  less  defi- 
nite is  our  knowledge  of  the  distribution  of  land  and  water. 
Although  no  remains  of  land  animals  have  yet  been  found,  we 
can  not  infei  from  this  negative  fact,  in  the  present  imperfect 
state  of  knowledge,  that  such  species  did  not  exist.  On  the  con- 
trary, many  of  the  fossils  indicate  shoal  water,  and  it  is  not  cred- 
ible that  the  surface  of  the  earth  should  have  been  so  adjusted  as 
to  have  been  one  shoreless  ocean,  yet  abounding  over  extensive 
areas  with  shoals.  There  must  have  been  archipelagos,  and  it  is 
probable  that  there  was  a  great  continent  occupying  the  area  of 
the  Atlantic.  This  is  inferred  from  the  manner  in  which  some 
formations  thin  out  westward,  where  also  they  are  of  finer  mate- 
rials. Both  of  these  facts  indicate  a  continent  on  the  east  as  the 
source  from  which  the  materials  were  derived. 

From  the  great  number  of  species  of  shells  in  the  Silurian 
system  within  the  State  of  New  York,  it  may  be  inferred  that  the 
climate  was  tropical,  or,  at  least,  much  warmer  than  it  is  now ;  for, 
at  the  present  time,  it  is  only  in  warm  regions  that  such  a  profu- 
sion of  species  is  found  in  such  limited  areas.  From  the  wide 
distribution  of  many  of  the  species  of  fossils,  it  may  also  be  infer- 
red that  the  climate  was  more  uniform  over  the  earth's  surface. 

CUMBRIAN    AND    CAMBRIAN    SERIES. 

In  ihe  north  of  England  and  in  Wales,  there  exist  certain 
slates,  and  other  more  or  less  metamorphic  strata,  on  the  precise 

What  is  said  of  the  fishes  ?  of  the  Scolithus  ?  of  the  probable  existence  of 
and  animals  ?  of  dry  land  ?  of  the  climate  ? 


284  TACONIC    ROCKS. 

relations  of  which  to  the  Silurian  system  there  has  been  a  dif 
ference  of  opinion.  It  is  generally  believed  that  they  belong  to 
the  older  part  of  the  great  Silurian  period,  since  the  fossiliferous 
strata  contain  species  of  fossils,  many  of  which  occur  also  in  the 
typical  Silurian  rocks.  Some  geologists,  however,  suppose  that 
a  part  of  these  rocks,  although  belonging  to  the  same  system,  are 
older  than  the  Caradoc  sandstone  and  the  Llandeilo  flags  (see  p. 
275),  while  others  consider  them  as  the  equivalents  of  those  rocks. 
English  geologists,  therefore,  describe  them  geographically,  and 
the  names  above  given  are  to  be  understood  geographically. 
They  do  not  indicate  well-established  systems  of  formations, 
having  peculiar  fossils  and  occupying  a  distinct  period. 

In  Pennsylvania,  also,  there  is  a  series  of  shales  lying  beneath 
the  Potsdam  sandstone. 

TACONIC    ROCKS. 

Certain  slates  and  limestones  in  the  western  part  of  Vermont 
and  Massachusetts,  and  in  the  adjacent  parts  of  New  York,  have 
been  called  Taconic  rocks.  They  have  been  supposed  by  Pro- 
fessor Emmons  to  constitute  a  system  of  formations  more  ancient 
than  the  Silurian  (New  York)  system.  A  few  very  rare  fossils 
occurring  in  the  slates  were  thought  to  characterize  them.  On 
page  117  we  have  given  a  section  of  Snake  Mountain,  in  Ver- 
mont, where  these  rocks  are  most  perfectly  exhibited.  Here 
they  are  found  to  contain  abundantly  the  same  species  of  fossils 
which  belong  to  the  Champlain  division  of  the  New  York  system. 

In  most  places  the  Taconic  rocks  have  been  so  much  disturbed 
and  altered,  that  their  proper  place  in  the  series  is  quite  obscure. 
They  are  semi-crystalline  and  much  jointed,  and  the  fossils  are 
mostly  obliterated.  It  is  convenient,  therefore,  to  retain  this 
name  as  designating  a  group  of  strata  more  or  less  metamorphic, 
but  of  which  a  part  certainly  and  probably  all  belong  to  the  Si- 
lurian system. 

Where  do  the  Cumbrian  rocks  occur  1  what  is  said  of  their  age  ?  what  dif- 
ference of  opinion  respecting  them  ?  Where  are  the  Taconic  rocks  ?  what 
is  said  of  the  fossils  in  them  ?  of  the  character  of  the  rocks  ? 


METAMORPHIC    AND    PRIMARY    STRATA  285 


CHAPTER  VIII. 
METAMORPHIC  AND  PRIMARY  STRATA 

WE  have  frequently  had  occasion  to  speak  of  metamorphic 
locks.  In  the  present  chapter  we  propose  to  give  a  brief  and 
general  account  of  them,  of  their  origin,  structure,  and  varieties. 

The  word  metamorphic  literally  signifies  changed  in  form,  and 
is  applied  to  such  stratified  rocks  as  have  lost,  in  a  greater  or  less 
degree,  their  original  structure.  The  mere  change  from  the  con- 
dition of  sand  or  mud  into  that  of  solid  rock  is  not  metamorphism, 
since  solid  strata  often  retain  their  original  structure  with  their 
fossils  in  a  good  state  of  preservation.  But  when  the  original 
mechanical  structure  of  the  strata  is  superseded  by  a  crystalline 
structure,  and  the  fossils  have  been  nearly  or  wholly  obliterated, 
the  rock  is  said  to  be  metamorphic. 

As  might  be  expected,  all  degrees  of  metamorphism  occur. 
Some  rocks  are  slightly  crystalline ;  their  fossils  are  indistinct, 
but  not  obliterated  ;  and  their  stratification  remains  quite  distinct, 
but  a  jointed  structure  has  been  superinduced.  Other  rocks  have 
lost  nearly  all  traces  of  their  origin  in  sand,  or  mud,  or  corals ; 
their  fossils  are  mostly  obliterated ;  and  they  contain,  in  few  lo- 
calities, only  indistinct  traces  of  organic  bodies.  Such  are  most 
of  the  Taconic  rocks.  But  there  are  extensive  regions,  as  in  the 
New  England  States,  in  which  the  rocks  are  wholly  crystalline 
in  their  structure,  and  are  entirely  destitute  of  organic  remains 
retaining  no  evidence  of  their  original  deposition  beyond  that  of 
stratification.  Even  this  has  disappeared  in  many  rocks  :  some, 
like  the  fine  slates,  assume  a  conspicuous  slaty  cleavage,  which 
is  often  independent  of  and  in  a  different  direction  from  their 
original  lamination,  which  is  now  indistinct.  Other  strata,  as 

What  is  the  meaning  of  metamorphic  ?  What  is  the  lowest  degree  of  met 
amorphism  ?  a  higher  degree  ?  What  is  the  most  complete  metamorphism  ? 


286  METAMORPHIC    AND    PRIMARY    STRATA. 

gneiss,  appear  to  have  been  more  or  less  perfectly  fused,  ana 
pass,  by  insensible  gradations,  into  unstratified  masses. 

Nearly  all  the  metamorphic  rocks  were  once  supposed  to  be 
older  than  the  Palaeozoic  formations.  They  were  included  in  the 
class  of  primary  strata,  and  were  supposed  to  have  been  deposited 
in  periods  anterior  to  the  existence  of  living  beings  on  the  surface 
of  the  earth.  But  most  of  the  so-called  primary  strata  have  suc- 
cessively been  identified  with  the  fossiliferous  strata.  The  origin 
of  others  is  yet  doubtful ;  and  some  lying  beneath  the  oldest  Pa- 
laeozoic formations  are  unquestionably  more  ancient.  Yet  we 
are  not  to  infer  from  the  absence  of  fossils  that  they  were  not 
originally  fossiliferous,  for  we  know  that  extensive  regions  consist 
of  rocks  of  the  same  structure  and  characters,  which  are  destitute 
of  fossils  only  because  they  have  been  subjected  to  intense  met- 
amorphic action,  while  most  of  the  oldest  rocks  which  retain 
their  original  structure  contain  fossils. 

The  true  primary  strata,  therefore,  are  rocks  which  are  more 
ancient  than  the  oldest  fossiliferous  strata,  which  had  probably  a 
similar  origin,  but  which  retain  no  evidence  of. the  existence  of 
organic  beings  during  the  periods  of  their  deposition.  They  are 
the  Ultima  Thule  of  our  geological  knowledge.  They  are  the 
limits,  not  of  the  facts  of  the  earth's  history,  but  of  our  means  of 
knowledge.  As  the  most  ancient  profane  history  of  man  is  lost 
iii  the  dimness  of  ancient  myths,  so  is  the  geological  history  lost 
in  the  obscure  teachings  of  these  most  ancient  metamorphic 
strata. 

The  principal  cause  of  metamorpTiism  is  the  power  of  crystal- 
lization, aided  by  heat  and  by  pressure.  It  is  well  known  that 
long-continued  intense  artificial  heat  may  change  the  structure  of 
stones.  Slabs  of  sandstone  in  furnaces  have  assumed  a  crystal- 
line structure  without  fusion.  But  the  strata  of  the  earth's  crust, 
being  prevented  by  the  mass  of  superincumbent  materials  from 
losing  the  heat  which  is  imparted  by  adjacent  volcanic  agencies 

What  was  once  supposed  to  be  the  age  of  metamorphic  strata  ?  What  di» 
we  know  of  some  of  them  ?  What  is  said  of  those  of  doubtful  age  ?  What 
are  primary  strata  ?  What  are  the  causes  of  metamorphism  ? 


METAMORPHIC    AND    PRIMARY    STRATA.  287 

are  thus  for  a  long  series  of  ages  subjected  to  this  metamorphic 
agency.  In  many  substances  the  power  of  crystallization  acts 
with  extreme  slowness.  It  is  probable,  therefore,  that  the  long 
continuance  of  intense  heat  has  produced  important  changes 
which  wor|ld  not  otherwise  have  occurred. 

It  is  well  known,  too,  that  great  pressure  with  heat  produces 
remarkable  effects.  By  this  means  chalk  has  been  converted  into 
marble.  A  degree  of  heat  which,  without  pressure,  would  de- 
compose the  substance,  with  pressure  merely  enables  the  crys- 
tallogenic  power  to  give  it  a  new  structure.  The  ancient  and 
the  metamorphic  limestones  were  once  in  the  condition  of  corals, 
of  chalk,  of  tufa,  and  of  other  calcareous  deposits  ;  but  by  heat 
and  pressure  they  have  been  converted  into  more  or  less  crystal- 
line marble. 

The  agencies  of  heat  and  pressure  also  exalt  the  power  of 
chemical  affinity,  and  enable  substances  to  enter  into  combina- 
tions, which  could  not  otherwise  have  been  formed.  Hence  the 
crystalline  strata  contain  a  great  number  of  minerals,  which  are 
never  found  in  unaltered  sedimentary  rocks.  If,  therefore,  met- 
amorphism  has  robbed  the  paleontologist  of  fossils,  it  has  en- 
riched the  mineralogist  with  some  of  the  choicest  treasures  of 
his  science. 

Metamorphism  not  only  obliterates  fossils  and  induces  a  crys- 
talline structure,  but  it  also  is  accompanied  by  the  introduction 
of  joints  and  a  slaty  cleavage. 

Joints  are  smooth  planes  of  division,  which  are  entirely  inde- 
pendent of  stratification.  They  usually  occur  in  two  or  more  sets 
of  planes,  which  cross  each  other  so  as  to  divide  the  rock  into 
prismatic  forms.  But  these  forms  are  incapable  of  subdivision. 

The  planes  of  slaty  cleavage  are  nearly  or  quite  parallel,  and 
produce  forms  which,  by  subdivision,  may  be  reduced  to  thin  lam- 
inae. Slaty  cleavage  is  sometimes  identical  with  the  lamination 
which  results  from  the  original  deposition  of  fine  sediment,  but 

How  has  time  aided  in  pi'oducing  changes  of  structure  ?     What  is  the  ef- 
fect of  pressure  ?     What  effect  of  heat  and  pressure  on  chemical  affinities 
What  are  joints  ?     What  is  said  of  slaty  cleavage  ? 


METAMORPHIC    AND    PRIMARY    STRATA. 

is  very  commonly  quite  independent  of  it.  In  the  latter  case  it 
is  often  extremely  difficult  to  detect  the  planes  of  deposition,  and 
geologists  have  been  sometimes  deceived  in  the  structure  of  such 
rocks. 

The  cause  of  joints  and  of  slaty  cleavage  is  yet  obscure.  That 
joints  are  not  exclusively  the  effect  of  igneous  agency,  appears 
from  their  occurrence,  although  rarely,  in  unconsolidated  clays  of 
the  latest  (the  pleistocene)  formation.  They  are,  however,  far 
more  common  in  metamorphic  rocks.  It  is  probable  that  the 
agency  is  somewhat  analogous  to  that  of  crystallization  ;  in  other 
words,  that  joints  are  the  effect  of  an  attraction  between  the  par- 
ticles of  mineral  matter. 

The  joints  of  conglomerate  rocks  often  divide  evenly  the  peb- 
bles which  lie  in  the  planes  of  division  in  the  partially  meta 
morphic  conglomerates  of  Roxbury  and  Dorchester,  in  Massa- 
chusetts. The  quarrymen  have  exposed,  often  to  the  extent  of 
snveral  rods,  smooth  surfaces,  which  have  been  formed  by  such 
joints  passing  evenly  through  all  the  various  materials  of  flinty 
and  slaty  pebbles,  and  of  coarse  and  fine  sand,  of  which  the  rock 
was  originally  constituted. 

The  principal  varieties  of  rocks  in  the  metamorphic  and  pri- 
mary strata  are,  clay  slate  (argillaceous  slate),  crystalline  marble, 
hornblende  slate,  quartz  rock,  mica  slate,  and  gneiss. 

Clay  slates  were  originally  deposits  of  clay,  the  odor  of  which 
may  be  perceived  when  they  are  moist.  As  roofing  and  graphic 
slates  they  are  well  known.  They  are  more  or  less  free  from  a 
gritty  composition,  as  the  clay  was  originally  more  or  less  free 
from  sand.  They  are  among  the  softer  rocks  ;  are  usually  dark- 
colored,  but  some  varieties  are  of  light  colors,  as  green,  drab,  &c. 

Crystalline  marble,  as  we  have  before  said,  was  originally  coral, 
or  chalk,  or  tufa,  and  has  been  crystallized  by  heat  under  pres- 
Bure.  When  pure,  it  is  white ;  but  many  metamorphic  regions 
abound  with  silicious,  micaceous,  or  argillaceous  strata,  which 

What  is  said  of  the  cause  of  joints  ?  of  joints  in  conglomerate  rocks  ?  Men- 
tion the  principal  varieties  of  metamorphic  rocks.  What  is  said  of  clay  slates  T 
of  crystalline  marble  ? 


METAMORPHIC    AND    PRIMARY    STRATA.  289 

are  also  calcareous.     Originally  such  strata  were  composed  of 
Band  or  mud,  with  more  or  less  ralcareous  matter. 

Hornblende  slate  consists  of  quartz  and  hornblende,  and  ig 
abundant  in  some  parts  of  the  New  England  States. 

Quartz  rock  is  composed  chiefly  of  quartz.  It  originated  prob- 
ably in  sandstone.  It  should  not  be  confounded  with  veins  of 
pure  quartz,  which  intersect  other  rocks,  anc"  which  are  not  of 
sedimentary  origin.  Quartz  rock  is  often  found  in  thick  beds, 
which  consist  of  nearly  pure  quartz,  and  retain  no  trace  of  lam- 
ination. It  is  then  a  very  hard  and  indestructible  rock.  But  it 
occurs  also  in  thinner  strata,  with  more  or  less  mica  in  its  com- 
position, and  then  passes  into  mica  slate. 

Mica  slate  consists  of  layers  more  or  less  thin,  that  are  com 
posed  of  quartz  and  mica,  with  the  scales  of  mica,  for  the  most 
part,  lying  nearly  or  quite  in  the  planes  of  lamination.  Well- 
crystallized  minerals,  as  garnets,  often  enter  more  or  less  into  its 
composition.  When  feldspar  in  considerable  quantity  is  added, 
it  becomes  gneiss. 

Gneiss  is,  therefore,  composed  of  the  three  minerals,  quartz, 
mica,  and  feldspar.  Its  composition  is  precisely  the  same  with 
that  of  granite,  but  it  differs  in  being  stratified.  Of  some  mount- 
ain masses  one  part  is  gneiss  and  another  part  is  granite,  this 
part  having  been  entirely  melted,  while  the  other  was  only  crys- 
tallized. 

One  of  the  most  interesting  examples  of  metamorphic  agency 
may  be  seen  in  the  crystalline  strata  of  the  western  part  of  the 
New  England  States.  Commencing  in  Canada,  they  occupy 
most  of  Vermont  and  the  western  parts  of  Massachusetts  and  of 
Connecticut.  These  rocks  have  been  much  disturbed  and  ele 
vated,  and  constitute  the  mountain  ranges  of  the  regions  which 
they  occupy.  For  many  years  they  were  supposed  to  be  primary 
strata,  until  at  length  the  frequent  identification  of  other  supposed 
primary  strata  with  Palaeozoic,  and  even  with  Mesozoic  forma- 
tions, led  to  a  more  diligent  search  for  fossils.  In  Canada  these 

What  is  said  of  hornblende  slate  ?  of  quartz  rock  ?  of  mica  slate  ?  of  gneiss  ? 
of  metamorphic  rocks  in  the  western  part  of  New  England  and  hi  Canada  T 

N 


290  UNSTRATIFIED    RCCKS. 

rocks  are  further  removed  from  the  great  source  of  metamorph* 
^c  agency,  which  was  in  New  England.  While,  therefore,  the 
search  for  fossils  was  unsuccessful  in  these  states,  in  that  prov- 
ince it  was  rewarded  with  the  discovery  of  a  few  specimens.  By 
these  the  rocks  in  question  were  shown  to  be  of  Silurian  age. 

The  All eghany  Mountains  constitute  another  belt  in  which  met 
amorphic  agency  has  oeen  exerted.  They  consist  mostly  of  De 
vonian  and  Silurian  formations,  which  are  partially  metamorphic 

The  source  of  metamorphic  action  may  usually  be  discovered 
in  the  greater  or  less  proximity  of  unstratified  rocks.  The  influ- 
ence of  those  which  are  called  hypogene  (see  description  of  the 
first  class  of  unstratified  rocks  in  the  next  chapter)  has  pervaded 
extensive  regions,  while  the  effects  of  the  Plutonic  rocks  (the 
second  class  in  the  same  chapter)  have  usually  been  more  local. 
The  influence  of  trap  rocks  has  generally  been  limited  to  a  few 
rods  or  a  few  feet,  while  that  of  granite  has  been  felt  for  many 
miles ;  but  in  the  island  of  Jamaica,  enormous  mountain  masses 
of  Plutonic  rocks  have  partially  altered  limestones  to  a  distance 
of  thirty  or  forty  miles. 


CHAPTER  IX. 

UNSTRATIFIED   ROCKS 

IN  our  history  of  the  changes  to  which  the  crust  of  the  globe 
Jias  been  subjected,  and  by  which  the  stratified  rocks  have  been 
formed,  we  have  briefly  noticed  those  irregular  masses  which  ap- 
pear to  have  been  forced  in  among  the  strata  by  igneous  action 
during  the  successive  geological  periods.  These  masses  are 
called  unstratified  or  igneous  rocks. 

We  have  now  reached  a  point  in  the  history  of  the  earth  be- 
yond which  the  succession  of  events  is  not  distinctly  recorded. 
If  stratified  rocks  older  than  those  already  described  ever  exist- 

What  is  said  of  fossils  in  metaraorphic  rocks  ?  of  the  Alleghany  Mountains  T 
of  the  source  of  metamorphic  agency  ?  What  point  in  the  history  of  the  earth 
has  now  been  reached  ? 


GRANITIC    ROCKS.  291 

ed,  as  most  geologists  believe,  all  known  traces  of  them  have 
been  obliterated  by  igneous  agency,  but  how  long  a  period  in- 
tervened between  the  oldest  known  strata  and  the  time  when  de- 
posits of  strata  commenced  it  is  impossible  to  determine.  We 
know,  however,  that  there  was  a  time  when  the  whole  crust  of 
the  earth  consisted  of  unstratified  rocks,  and  that  these  rocks 
formed  the  base  on  which  all  the  strata  repose,  and  out  of  which 
the  primitive  strata  were  formed. 

This  mass  or  crust  was  probably  granite,  a  compound  of  quartz, 
mica,  and  hornblende.  Granite  is  so  various  in  composition  and 
structure,  and  has  been  erupted  at  so  many  different  periods,  that 
we  can  ascend  the  stream  of  time  no  further  to  note  the  success- 
ive changes  in  the  mineral  masses,  and  designate  the  epochs  of 
geological  history.  It  only  remains,  therefore,  to  give  a  short 
description  of  the  various  kinds  of  unstratified  rocks. 

There  are  about  eight  varieties  of  unstratified  rocks.  They 
may  be  arranged  in  three  classes,  the  Granitic,  the  Trappean,  and 
the  Volcanic  rocks 

SECTION  I.-GRANITIC  ROCKS. 

In  this  class  of  unstratified  rocks  may  be  included  Granite,  Sy* 
enite,  and  Quartz. 

I.  Granite. — True  granite  is  a  triple  compound  of  quartz,  feld- 
spar, and  mica.  The  proportions  and  arrangements  of  these 
simple  minerals  are  indefinitely  varied.  There  are  very  coarse 
granites,  in  which  large  crystals  of  the  constituent  minerals  are 
united  to  each  other ;  and  there  are  very  fine-grained  granites, 
in  which  it  is  difficult  to  distinguish  the  different  ingredients. 
Between  these  extremes  there  is  every  variety  of  structure  and 
composition,  although  feldspar  is  generally  found  in  the  largest 
proportion. 

What  was  the  condition  of  the  earth  before  stratification  commenced  ? 
Which  is  probably  the  oldest  igneous  rock  ?  What  is  said  of  it  ?  Why  can 
we  not  ascend  the  stream  of  time  further  ?  How  many  kinds  are  there  of 
unstratified  rocks?  How  may  they  be  classed?  What  rock«  belong  to  th& 
first  class?  Describe  true  granite. 


292 


GRANITIC    ROOKS. 


1.  Varieties  of  Granite. — "When  the  rock  is  nearly  or  quite  des 
titute  of  mica,  the  quartz  and  feldspar  present  a  surface  which 
resembles  written  characters,  on  which  account  it  is  called  graph- 
ic granite.  The  following  figures  represent  the  appearance  of 
the  surface.  Fig.  209  is  a  section  in  the  same  direction  with  the 
laminae,  and  Fig.  210  is  a  portion  of  the  surface  of  a  rock  found 


Fig.  209. 


Fig.  210. 


GRAPHIC    GRANITE,   GOSHEN,    MASS. 


in  Goshen,  Mass.  (Hitchcock's  Report),  and  is  a  good  example  of 
this  variety  of  granite. 

2.  When  the  crystals  of  feldspar  are  very  distinct,  the  rock  is 
called  porphyritic  granite. 

3.  Talc  sometimes  takes  the  place  of  the  mica;  the  rock  is 
then  designated  as  talcose  granite,  and  is  called  by  the  French 
protogene.     By  the  decomposition  of  this  rock  there  is  formed 
the  celebrated  porcelain  clay,  so  extensively  used  in  pottery. 

4.  When  the  rock  is  mostly  feldspar,  it  is  called  feldspathic 
granite. 

All  these  varieties,  however,  often  gradually  pass  into  each 
other,  and  also  into  the  other  kinds  of  unstratified  rocks. 

The  color  of  granite  is  also  very  various,  although  it  is  usually 
grayish  white  or  flesh  colored. 

II.  Syenite. — Syenite  is  similar  to  granite  in  structure,  but  dif- 
fers from  it  in  composition.  Hornblende  takes  the  place  of  the 
mica,  and  imparts  to  the  rock  a  darker  color.  It  is  generally  a 
fine-grained  rock.  Mica  is,  however,  often  present  in  this  rock, 
and  it  is  then  called  syenitic  granite. 

Describe  graphic  granite.  What  is  said  of  the  three  varieties  of  granite  f 
Describe  syenite,  its  composition  and  varieties 


GEOGRAPHICAL    DISTRIBUTION    OF    GRANITIC    ROCKS. 

The  term  syenite  is  derived  from  Syene,  in  Upper  Egypt, 
whence  most  of  the  rocks  used  in  the  construction  of  ancient 
Egyptian  monuments  were  obtained.  This  rock,  however,  is 
found  to  be  a  red  granite,  containing  black  mica  and  minute  por- 
tions of  hornblende,  while  Sinai,  in  Arabia,  is  composed  of  a  true 
syenite. 

III.  Quartz  Rock. — The  mineral  quartz  often  exists  in  such 
masses  as  to  be  entitled  to  a  place  among  the  unstratified  rocks. 
It  sometimes  occurs  in  thin  seams,  or  in  regular  layers,  in  which 
cases  it  probably  had  an  aqueous  origin  ;  but  large  dikes  of  quartz 
not  unfrequently  occur  among  the  strata  in  such  forms  as  to  in- 
dicate an  igneous  origin.     Large  mountains  sometimes  consist 
mostly  of  quartz.     It  is  distinguished  as  the  rock  with  which  gold 
is  usually  associated. 

IV.  Geographical  Distribution  of  Granitic  Rocks. — The  rocks 
of  this  class  are  widely  distributed  over  the  surface  of  the  earth 
They  frequently  form  extensive  mountain  ranges,  but  are  gener- 
ally associated  with  the  non-fossiliferous  or  metamorphic  strata. 

Granite  occurs  in  various  parts  of  New  England.  It  is  found 
in  bands  and  patches  extending  across  the  eastern  portion  of 
Massachusetts.  Commencing  at  Andover,  a  belt  of  granite  pass- 
es, in  a  southwest  direction,  to  Rhode  Island,  having  the  mica 
and  clay  slates  on  the  west,  and  porphyry  and  syenite  on  the  east. 
Another  belt  extends  from  Buzzard's  Bay,  in  a  northeast  direc- 
tion, to  Cape  Ann. 

Granite  and  syenite  are  quarried,  for  building  purposes,  in  many 
places  near  Boston.  The  most  celebrated  localities  of  the  lattei 
are  at  Quincy  and  Braintree. 

West  of  these  belts,  in  various  parts  of  New  England,  granite 
is  found  in  patches,  some  of  which  are  of  great  extent,  as  in  Es 
sex  county,  Vermont,  and  in  many  portions  of  New  Hampshire, 
Maine,  and  along  the  range  of  the  Green  Mountains.     It  is  also 
often  met  with  in  the  Middle,  Southern,  and  Western  States. 

From  what  is  the  name  derived  ?  How  has  quartz  originated  ?  For  what 
is  it  distinguished  ?  Where  are  granitic  rocks  found  in  New  England  ?  io 
other  portions  of  the  United  States  ? 


294  POSITION    AND    AGE    OF    GRANITIC    ROCKS. 

On  the  western  coast  of  the  United  States  granitic  rocks  ex- 
tend along  the  whole  range  of  the  Rocky  Mountains,  and  through- 
out the  Andes,  in  South  America.  In  some  places  among  the 
Andes,  granite  rises  to  an  elevation  of  12,000  feet. 

Spires  of  granite  among  the  Alps,  in  Europe,  are  of  great 
height,  as  in  the  case  of  the  Aiguille  de  Dree,  which  is  a  solid 
shaft  elevated  4000  feet  above  its  base. 

Quartz  rocks  abound  in  California,  and  constitute  the  guanqua 
of  the  inexhaustible  deposits  of  gold  which  have  so  recently  been 
discovered  in  that  state. 

V.  Geological  Position  and  Age. — Granitic  rocks  are  generally 
associated  with  the  metamorphic  strata,  either  existing  in  large 
belts  or  masses,  or  cutting  the  strata  in  the  form  of  dikes.  They 
are  not,  however,  confined  to  the  older  strata,  but  often  penetrate 
the  coal-beds,  and,  in  a  few  cases,  extend  as  high  up  as  the  ter- 
tiary ;  hence  these  rocks  have  been  erupted  at  different  periods 
during  the  deposition  of  the  stratified  masses.  This  inference  is 
confirmed  by  the  chemical  and  mechanical  effects  which  granitic 
dikes  have  produced  upon  each  other  and  upon  the  strata. 

The  following  figure  of  a  bowlder  found  at  West  Hampton, 
Fig.  211.  Massachusetts  (Hitchcock's  Re- 

port), will  illustrate  the  kind  of 
proof  which  these  rocks  present 
,  of  the  truth  of  this  statement. 

a  represents  the  bowlder, 
which  is  a  genuine  granite. 
b  c  d  a  vein  of  granite  passing 
directly  through  it.  fe  is  a  second  vein,  which  cut  off  the  first, 
and  removed  it  upward,  g  k  is  a  third  vein,  which  cut  off  the 
other  two.  Each  of  the  veins  is  of  different  varieties  of  granite. 
In  this  case  we  have  four  distinct  periods  of  ejection.  Similar 
sxamples  are  found  among  all  the  metamorphic  rocks.  It  is 
hence  inferred  that,  although  some  of  the  granites  are  the  oldest 

Where  are  granitic  rocks  found  in  South  America  ?  in  the  Alps  ?  What 
raluable  metal  is  usually  associated  with  this  class  of  rocks  ?  What  is  the  geo- 
*>gical  position  of  granite  ?  What  evidence  of  different  periods  of  eruption  T 


TRAPPEAN    ROCKS.  295 

*f  the  rocks,  others  have  been  formed  at  different  epochs,  and 
can  not,  therefore,  be  assigned  to  any  particular  period  of  the 
earth's  history. 

SECTION  II.— TRAPPEAN  ROCKS. 

Under  this  division  we  include  porphyry,  greenstone,  trachite, 
basalt,  and  amygdaloid. 

These  rocks  are  composed  mostly  of  feldspar  and  hornblende, 
or  augite.  The  term  trap  is  derived  from  the  Swedish  word 
trappa,  a  stair,  and  applied  to  this  class  because  they  often  con- 
sist of  blocks  arranged  like  steps. 

I.  Porphyry. — The  term  porphyry  is   applied  rather  to  the 
structure  of  rocks  than  to  their  composition.     The  ancient  por. 
phyries  have  a  base  of  compact  feldspar,  through  which  are  dis- 
tributed crystals  of  feldspar.     This  formed  a  very  hard  and  du- 
rable rock,  capable  of  receiving  a  very  high  polish.     Any  rock, 
however,  with  a  homogeneous  base  containing  crystals  of  some  of 
the  simple  minerals  disseminated  through  it,  is  called  porphyry. 
Hence  we  have  greenstone  porphyry,  which  has  a  base  of  green 
stone,  clay  stone  porphyry,  pitchstone  porphyry ,  trachy  tic  porphyry , 
&c.     The  ancient  porphyries  were  purple,  hence  the  name  ;  but 
each  variety  has  a  different  color. 

II.  Greenstone. — This  term  includes  the  compact  varieties  of 
the  class  in  which  hornblende  predominates,  and  imparts  to  the 
rock  a  greenish  color.     The  structure  is  often  porphyritic,  or  very 
coarse  grained,  in  which  case  it  is  designated  as  porphyritic  green- 
stone and  syenitic  greenstone. 

III.  Trachyte. — This  rock  consists  of  glassy  feldspar,  horn- 
blende, mica,  and  titaniferous  iron  ore.     It  has  a  rough  surface, 
on  which  account  it  has  received  its  name.     Its  structure  is  por- 
phyritic, and  its  color  of  a  grayish  white. 

IV.  Basalt. — This  is  a  compact,  fine-grained  variety  of  the 

What  is  the  inference  respecting  the  age  of  granite  ?  What  is  the  compo- 
sition and  structure  of  the  trappean  rocks  ?  How  is  the  term  porphyry  used? 
What  is  said  of  the  ancient  porphyries  ?  of  greenstone  ?  of  trachyte  ?  What 
is  basalt? 


296  TRAPPEAN    ROCKS. 

trap  family,  and  is  similar  in  composition  to  greenstone,  although 
it  contains  the  variety  of  hornblende  called  augite,  with  distinct 
grains  of  olivine.  Its  color  is  black,  or  grayish  black.  The  rock 
can  not  easily  be  distinguished  from  greenstone. 

V.  Amygdaloid. — This  term,  like  porphyry,  is  applied  to  the 
structure  of  certain  rocks   of  the  trap  family.     It  abounds  in 
rounded  cavities,  which  are  filled  with  quartz,  chalcedony,  cal- 
careous spar,  and  some  other  minerals.     This  gives  a  peculiar 
texture  to  the  rock,  so  that  it  appears  like  paste  filled  with  al- 
monds, hence  its  name.     The  softer  base  is  called  wacke,  which 
is  sometimes  destitute  of  vesicles. 

VI.  Columnar  Structure  of  the  Trap  Rocks. — Rocks  of  the  trap 
family  and  some  others  are  often  distinguished  by  their  columnar 
structure.     They  are  divided  into  prisms,  which  are  more  or  less 
regular,  with  from  three  to  eight  faces,  and  from  a  few  feet  to 
200  feet  in  length.     These   columns  are  generally  divided  by 
joints,  and  the  sections  are  usually  concave  at  the  top  and  con- 
vex at  the  bottom ;  although  the  form  is  sometimes  reversed,  as 
at  Titan's  Pier,  Mount  Holyoke,  Massachusetts. 

The  following  view  of  the  Giant's  Causeway,  Ireland,  Fig.  212, 

Fig.  213. 


THE    GIANT  S    CAUSEWAY. 


shows  the  position  of  these  columns.     The  columns  are  pentag- 
onal, and  from  one  to  five  feet  in  diameter. 

Fingal's  Cave,  on  the  island  of  Staffa,  is  another  example  of 
the  same  structure  (Fig.  213). 

These  columns  sometimes  stand  perpendicularly  to  the  hori- 
What  is  amygdaloid  ?     What  is  said  of  the  stricture  of  the  trappean  rocks  ? 


GEOGRAPHICAL    DISTRIBUTION    OF    TRAP    ROCKS. 
Fig.  213. 


297 


Fig.  214. 


BASALTIC    DIKE,   N.   CAROLINA. 


FINGAL'S  CAVE,  STAFFA. 

zon,  and,  when  broken  and  disinte 
grated  by  the  action  of  the  atmos- 
phere or  of  the  waves,  present  the 
appearance  of  ruined  castles.  When 
they  are  horizontal,  they  appear  like 
walls,  and  have  often  been  mistaken 
for  ancient  fortifications  ( Fig.  214). 
The  cause  of  this  peculiar  columnar  structure  is  believed  to  be 
a  tendency  of  the  matter,  when  cooling,  to  assume  a  globular  form, 
and  this  view  is  confirmed  by  the  fact  that  the  same  structure  is 
found  in  recent  lavas  and  in  the  clay  of  furnaces,  but  it  has  been 
more  satisfactorily  verified  by  the  experiments  of  Watt,  who 
melted  700  pounds  of  basalt  and  allowed  it  slowly  to  cool.  In 
this  process  the  matter  gradually  separated  into  globular  masses, 
and  these,  by  pressing  against  each  other,  were  finally  formed  into 
regular  columns. 

VII.  Geographical  Distribution. — Trap  rocks  are  found  in 
mountain  ranges  and  in  the  form  of  dikes,  which  have  cut  througn 
the  strata  in  nearly  every  part  of  the  earth's  crust. 

In  the  U.  States,  trap  rocks  occur  on  the  Kennebec  River,  in 
Maine,  where  they  rise  in  mountain  masses  from  200  to  300  feet 
in  height,  and  trap  dikes  are  found  in  every  portion  of  the  state. 

What  is  the  position  and  appearance  of  the  columns?  What  is  the  cause 
of  the  columnar  structure  ?  How  is  this  proved  ?  Where  do  trappean  rock* 
occur  in  New  England? 

N2 


TR  iPPEAN    ROCKS. 

North  and  south  of  Boston,  Massachusetts,  there  is  a  belt  of 
greenstone  associated  with  porphyry,  which  makes  its  appear- 
ance at  Nahant,  Lynn,  Charlestown,  Roxbury,  and  many  other 
places.  The  ridges  are  sometimes  500  feet  in  height.  Another 
ridge  of  greenstone  passes  along  the  Connecticut  River  valley 
from  West  Rock,  in  New  Haven,  nearly  to  Vermont.  It  includes 
Mounts  Tom  and  Holyoke,  which  are  elevated  a  thousand  feet 
or  more  in  height.  In  the  valley  of  Lake  Champlain  numerous 
naked  dikes  occur.  A  few  miles  above  the  city  of  New  York 
greenstone  trap  forms  a  series  of  elevations  called  the  Palisades. 
Three  ridges  pass  through  the  State  of  New  Jersey,  and  beds 
and  high  summits  make  their  appearance  at  least  as  far  south 
as  North  Carolina. 

But  the  most  extensive  ranges  of  trap  are  found  west  of  the 
Rocky  Mountains.  The  Columbia  River  passes  through  mount- 
ains of  trap  from  400  to  1000  feet  high.  The  following  figure 
exhibits  the  appearance  of  the  rocks. 

Fig.  215. 


BASALTIC    COLUMNS,    COLUMBIA    RIVER. 


Where  do  trappean  rocks  occur  in  New  York  and  New  Jersey  ?    What  other 
localities  ? 


VOLCANIC   ROCKS.  299 

A  belt  of  trap  aoout  three  miles  wide  and  one  hundred  and 
thirty  miles  long  extends  along  the  Bay  of  Fundy,  Nova  Scotia. 
The  action  of  the  waves  has  exposed  vast  columns  of  greenstone, 
from  300  to  400  feet  in  height.  Many  beautiful  minerals,  such 
as  quartz  crystals,  agate,  chalcedony,  amethyst,  and  specular  iron, 
abound  in  this  range.  Some  valuable  ores  are  associated  with 
greenstone  dikes,  particularly  the  ores  of  copper,  as  those  of  Lake 
Superior,  Connecticut,  and  New  Jersey. 

Trap  rocks  are  very  extensively  developed  in  the  Andes,  on 
the  Eastern  Continent.  In  New  South  Wales,  basaltic  mountains 
rise  to  the  height  of  four  thousand  feet,  and  present  phenomena 
similar  to  those  of  Staffa.  These  rocks,  however,  are  found  in  so 
many  localities,  that  our  limits  forbid  a  further  enumeration. 

VIII.  Geological  Position  of  the  Trap  Rocks. — Trap  rocks  are 
protruded  through  all  the  strata  from  the  earliest  times  down  to 
the  close  of  the  tertiary  period.  There  appears  to  have  been 
two  periods,  however,  during  which  they  were  erupted  in  the 
greatest  abundance.  The  greenstone,  which  is  associated  with 
the  new  red  sandstone,  and  the  basalt  of  the  tertiary,  form  the 
most  extensive  ranges  or  masses  of  this  class  of  unstratified 
rocks. 

SECTION  III.— VOLCANIC  ROCKS. 

This  division  of  the  unstratified  rocks  includes  all  the  mineral 
substances  ejected  from  volcanic  craters.  The  term  lava  has 
been  applied  to  this  matter  from  the  fact  of  its  flowing  out  in  a 
liquid  form. 

Lava  is  composed  mostly  of  feldspar  and  augite,  although  a 
iarge  number  of  the  other  simple  minerals  are  found  distributed 
through  it,  one  hundred  species  having  been  found  in  the  prod- 
ucts of  Vesuvius. 

Lavas  are  of  several  kinds,  which  differ  in  structure,  composi- 
tion, and  color.  In  the  dark-colored  lavas,  augite  constitutes  a 

What  is  the  geological  age  and  position  of  the  trappean  rocks  ?  During  what 
periods  were  they  erupted  in  the  greatest  abundance?  What  rocks  are  in- 
cluded in  the  vol  janic  class  ?  Describe  the  different  varieties  of  lava. 


300  EXTINCT    VOLCANOES. 

considerable  portion ;  and  in  the  light-colored  lavas,  feldspar  is 
the  principal  ingredient. 

1.  When  feldspar  preponderates,  the  lavas  are  called  tracJiytic, 
and  resemble  trachyte.     The  structure  depend  upon  the  mode 
of  cooling.    The  interior  of  the  mass,  or  those  portions  which  are 
cooled  under  pressure,  are  compact ;  but  the  surface,  which  is 
exposed  to  the  air,  is  exceedingly  porous,  and,  when  ejected  into 
water,  so  light  as  to  swim  upon  the  surface  in  the  form  of  pumice. 

2.  When  augite  is  the  principal  ingredient,  basaltic  lavas  re- 
sult.    These  can  hardly  be  distinguished  from  basalt;  in  fact, 
when  cooled  under  pressure,  they  form  compact  basalt,  but,  when 
cooled  in  the  open  air,  they  become  filled  with  vesicles,  and  are 
generally  termed  scoria. 

3.  A  variety  of  lava  called  graystone  lava  is  intermediate  be- 
tween the  trachytic  and  basaltic  lavas.      Vitreous  lavas,  obsidian, 
and  pitchstone,  are  similar  to  melted  glass. 

4.  The  materials  which  are  ejected  from  volcanoes  during  an 
eruption,  in  the  form  of  fine  powder  and  angular  fragments,  fall 
down  upon  the  neighboring  land  or  sea,  and  there  becoming 
mixed  with  sand  or  shells,  form  a  peculiar  rock  called  tuff.     The 
varieties  are  denominated  trap  tuff,  volcanic  tuff,  volcanic  breccia, 
tufaceous  breccia,  &c.     Many  other  substances  are  ejected  from 
volcanoes,  but  they  are  of  little  geological  interest.     We  have 
given  on  p.  67  the  geographical  distribution  of  volcanic  vents. 

EXTINCT    VOLCANOES. 

Extinct  volcanoes  are  very  numerous,  and  the  materials  they 
have  ejected  are  similar  to  the  lavas  and  basalts  of  the  present 
period.  The  evidence  of  their  existence  during  the  tertiary  pe- 
riod has  been  presented  p.  181.  From  their  size  and  appearance 
it  is  inferred  by  many  geologists  that  volcanic  agency  was  ex- 
erted on  a  much  more  extensive  scale  than  at  present,  and  that 
it  lias  been  diminishing  from  the  earliest  geological  times. 

What  is  said  of  extinct  volcanoes  ? 


ORIGIN    OF    UNSTRATIFIED    ROCKS.  301 

SECTION  IV.— ORIGIN  OF  THE  UNSTRATIFIED  ROCKS. 

We  now  proceed  to  give  a  summary  of  the  evidence  which  is 
relied  upon  to  prove  the  igneous  origin  of  the  unstratified  rocks. 
This  evidence  may  be  presented  under  the  following  heads :  I. 
Their  structure  and  composition;  II.  Their  position;  and,  III. 
Their  effects  upon  the  strata. 

I.  The  structure  and  composition  of  the  unstratified  rocks  prove 
their  igneous  origin.  Commencing  with  the  lavas  of  existing 
volcanoes,  of  whose  igneous  origin  there  can  be  no  doubt,  ^ve 
notice  the  same  structure,  and  often  the  same  constituents  in  the 
extinct  volcanoes,  in  all  the  trachytes  and  in  basalt.  So  com- 
plete is  the  evidence  derived  from  physical  and  chemical  char- 
acters, that  most  rocks  of  the  trap  family,  when  isolated  from  their 
position,  can  with  difficulty  be  distinguished  from  many  vari«j 
ties  of  lava.  This  resemblance  is  not  so  perfect  in  rocks  of  tin 
granitic  class,  and  yet  granite  and  syenite  often  assume  the  trap 
pean  structure.  The  crystals  are  more  distinct,  a  fact  which  is 
accounted  for  on  the  supposition  that  they  were  formed  under 
the  ocean  or  deep  in  the  earth,  and  were  more  slowly  cooled. 
There  is  also  considerable  difference  in  their  composition,  but 
all  the  unstratified  rocks  by  almost  insensible  gradations  pass  into 
each  other,  the  lavas  into  trachyte,  trachyte  into  greenstone,  ami 
greenstone  into  porphyry  and  granite. 

Jil.  The  position  of  the  unstratified  in  relation  to  the  stratified 
rocks  shows  that  at  the  time  of  their  formation  they  were  in  ji 
melted  or  plastic  state.  Dikes  oi  each  variety  not  only  pass  di- 
rectly through  the  strata,  but  they  spread  out  laterally,  filling  up 
the  cavities  and  flowing  over  the  surfaces  of  the  strata.  The  ap 
pearance  of  the  dikes  is  precisely  similar  to  those  in  volcanic 
mountains,  where  rents  are  often  made  for  miles  in  extent,  and 
filled  with  melted  lava.  The  principal  difference  is,  that  the 
trap  and  granitic  dikes  are  on  a  much  larger  scale,  and  of  much 
greater  extent.  They  occupy  every  pDsition  which  would  be 

What  was  the  origin  of  the  unstratified  rocks?  What  is  the  first  proof  of 
this?  the  second  proof! 


302 


ORIGIN    OF    UNSTRATIFIED   ROCKS. 


assumed  by  matter  in  a  state  effusion,  ejected  among  the  strata 
by  an  upward  force,  as  seen  in  the  following  figure. 

Fig.  216. 


GRANITIC    DIKE   IN   LIMESTONE,  DERBY,  TT. 

III.  The  mechanical  and  chemical  effects  of  the  unstratified 
rocks  upon  the  strata  and  upon  each  other  prove  their  igneous  or- 
igin. The  strata  are  lifted  up,  broken,  and  plicated  on  each  side 
of  dikes,  greenstone,  and  granitic  ridges,  showing  that  the  latter 


Fig.  217. 


GRANITE    DIKE. 


were  forced  up  from  beneath ; 
and  there  are  many  examples  in 
which  portions  of  the  stratified 
rock  through  which  granitic  and 
trap  dikes  pass  are  inclosed  in  their 
substance.  This  seems  conclusive 
as  to  the  igneous  condition  of  the 
matter  when  it  was  erupted.  Fig. 
217  is  an  example  of  this  kind  of 
agency  (Hitchcock's  Report). 
The  strata  in  contact  with  the  dikes,  and  often  to  a  considerable 
distance  from  them,  are  altered  in  texture  and  composition  in  a 
manner  precisely  similar  to  rocks  which  have  been  subjected  to 
volcanic  action.  Dikes  of  granite  passing  through  beds  of  chalk 
have  converted  the  chalk  into  crystalline  marble.  The  same  effect 
has  been  produced  upon  chalk  by  heating  it  confined  in  an  iron 
vessel.  Copper  ores  through  which  greenstone  dikes  have  been 
thrust  have  been  smelted  and  converted  into  pure  metal.  Exam 
pies  of  this  effect  are  met  with  in  Nova  Scotia,  Lake  Superior  cop- 
per mines,  and  in  many  other  places  where  copper  ore  is  found. 

What  is  the  third  proof  of  the  origin  of  unstratified  rocks  ?  Describe  the 
chemical  and  mechanical  effects  of  dikes  upon  chalk,  coal,  and  other  strata 
through  which  they  pass. 


ORIGIN    OF    STRATIFIED   ROCKS.  303 

Similar  chemical  effects  have  been  produced  upon  the  coal- 
oeds.  In  the  eastern  portions  of  the  great  Appalachian  coal-field, 
die  anthracite  coal  is  found  in  the  vicinity  of  the  unstratified 
rocks ;  and  we  know  that  heat  will  drive  out  the  bituminous  mat- 
ters from  soft  coal,  in  which  case  it  resembles  anthracite.  That 
the  anthracite  was  originally  bituminous  is  proved  by  its  struc- 
ture, and  by  the  fact  that,  in  passing  in  a  northwest  direction 
across  this  coal-field,  the  bituminous  matter  gradually  increases, 
until,  at  a  considerable  distance  from  the  unstratified  rocks,  its 
original  bituminous  character  prevails.* 

Generally,  near  the  dikes  the  strata  are  more  crystalline,  and 
this  is  a  well-known  effect  of  heat. 

We  find,  also,  many  examples  where  one  dike  has  cut  off  an- 
other. A  horizontal  dike  has  been  cut  off  and  lifted  up  by  one 
which  is  vertical.  This  is  so  frequently  the  case  with  granite 
(page  294)  and  greenstone,  that  no  doubt  can  be  entertained  by 
any  one  who  has  witnessed  the  phenomena  of  the  igneous  origin 
of  the  whole  class  of  unstratified  rocks. 

SECTION  V.— ORIGIN  OF  THE  STRATIFIED  ROCKS. 

The  stratified  rocks,  as  we  have  abundantly  shown,  received 
their  structure  and  regular  arrangement  through  the  immediate 
agency  of  water.  But  the  materials  of  many  of  them,  especially 
of  the  older  strata,  were  evidently  derived  directly  from  the  ig- 
neous rocks.  The  composition  of  gneiss,  which  is  believed  to  be 
the  oldest  stratified  rock,  is  identical  with  that  of  granite.  Gran- 
ite often  passes  into  gneiss  so  gradually  as  to  show  that  in  early 
times  the  same  materials  were  alternately  acted  upon  by  fire  and 
water,  and  that  they  existed  at  one  time  in  a  stratified,  and  at 
others  in  an  unstratified  condition. 

The  various  classes  of  slates,  as  mica  slate,  talcose  slate,  and 
argillaceous  slate,  appear  to  have  been  derived  from  granitic 
rocks  which  had  been  subjected  to  chemical  and  mechanical 
*  This  is  doubted  by  some  geologists. 

How  have  the  stratified  rocks  been  formed  1  In  what  state  were  their  ma- 
terials before  stratification  commenced  ?  What  proof  of  this  ? 


304  NEBULAR    HYPOTHESIS. 

agencies.  In  different  parts  of  the  stratified  series  we  often  find 
conglomerates  which  are  composed  of  pebbles  of  igneous  and 
aqueous  rocks,  cemented  together  by  finer  materials. 

From  the  above  facts,  and  from  those  stated  in  the  preceding 
section,  it  is  an  obvious  inference  that  tlie  whole  crust  of  the  globe 
accessible  to  observation  was  once  in  a  melted,  state. 

We  have  already  presented  the  evidence  for  believing  that  the 
interior  of  the  earth  is  at  the  present  time  subjected  to  intense 
heat  (p.  7C) ;  so*that  we  have  now  traced  back  the  history  of  our 
planet  to  a  period  when  its  entire  mass  was  in  a  state  of  igneous 
fluidity. 

In  confirmation  of  this  condition  of  the  earth  at  some  former  pe- 
riod, the  supposed  igneous  state  of  other  bodies  of  the  solar  system 
has  been  frequently  urged.  The  moon  appears  to  have  been  sub- 
jected, at  no  very  distant  period,  to  intense  igneous  agency. 
The  sun,  and  some  of  the  planets,  have  also  been  supposed  to  be 
pervaded  with  intense  heat  at  the  present  time.  This,  however,  is 
merely  an  hypothesis  :  their  actual  condition  is  unknown. 

SECTION  VI.— NEBULAR  HYPOTHESIS. 

It  has  been  a  question  much  discussed  by  astronomers,  wheth- 
er the  earth,  the  solar  system,  and  the  whole  material  universe, 
were  once  in  a  state  of  vapor.  The  subject  is  designated  the 
nebular  hypothesis.  The  hypothesis  supposes  that  the  matter  of 
which  the  universe  is  composed  existed  as  vast  nebulae,  out  of 
which,  by  the  laws  of  gravity  and  of  centrifugal  force,  under  the 
molding  hand  of  God,  the  present  system  of  the  world  has  been 
formed. 

If  we  suppose  that  God  created  matter  and  diffused  it  through- 
out space,  and  that  from  time  to  time  he  gradually  molded  it  into 
suns  and  planets,  under  the  laws  of  attraction  which  he  has  im- 
pressed upon  material  atoms,  we  shall  have  all  the  conditions  re- 
quired to  account  for  the  present  arrangement  of  the  universe. 

What  inference  in  respect  to  the  early  condition  of  the  earth  ?  What  anal- 
ogies are  m-ged  in  confirmation  of  this  1  What  question  has  been  much  dis- 
cussed by  astronomers  ?  Give  a  description  of  the  nebular  hypothesis. 


NEBULAR    HYPOTHESIS.  305 

There  are  many  arguments  which  are  relied  on  to  establish 
the  truth  of  this  hypothesis.  An  important  one  is  furnished  by 
the  condition  of  the  earth's  crust. 

If  we  assume  that  the  matter  of  the  solar  system  existed  at  first 
as  a  nebula,  there  would  be  a  tendency,  from  the  action  of  grav- 
itation, in  all  the  atoms  to  move  toward  the  center,  a  solid  nucleus 
would  be  formed  by  condensation,  and  the  latent  heat  would  ren- 
der it  fluid. 

By  the  meeting  of  opposite  currents  a  revolution  would  soon 
be  established,  and  the  matter  on  the  circumference  of  this  vast 
nebula  would  become  so  dense  that  the  centrifugal  force  would 
overcome  the  cohesion,  and  a  ring  would  be  separated  from  the 
mass.  This  ring,  as  the  nebula  left  it,  by  its  further  condensa 
tion  would  be  collected  into  a  globe,  which  would  be  fused  by 
the  development  of  its  latent  h^at.  The  same  process  would  be 
repeated  until  all  the  planets  were  formed,  and  by  the  same  law 
the  planets  would  throw  off  their  satellites. 

Now  we  have  shown  that  the  earth  was  once  in  the  precise 
condition  which  such  a  process  would  produce,  that  is,  in  the 
state  of  fusion  from  heat. 

All  the  facts  and  phenomena  connected  with  the  present  con- 
dition of  the  earth  and  of  the  solar  system  are  either  accounted 
for  by,  or  consistent  with,  this  hypothesis.  The  planets  all  move 
in  the  same  direction  in  their  orbits.  They  lie  very  nearly  in  the 
plane  of  the  ecliptic.  They  are  all  compressed  at  their  poles  and 
enlarged  at  their  equators,  a  condition  which  would  result  from 
the  action  of  the  centrifugal  force.  Many  bodies,  as  the  comets, 
exist  as  nebulous  matter,  and,  in  various  portions  of  the  heavens, 
the  telescope  has  revealed  to  us  numerous  objects  which  are  be- 
lieved by  some  to  be  matter  in  a  nebulous  condition. 

This  hypothesis  is  adopted  by  many  astronomers,  and  many 
learned  treatises  have  been  written  in  its  support,  the  most  cele- 
brated of  which  is  the  Mecanique  Celeste  of  La  Place. 

It  should  be  observed,  however,  that  many  nebulae  have  lately 
been  resolved  by  powerful  telescopes,  especially  by  the  large  re- 
What  are  the  proofs  of  the  truth  of  the  nebular  hypothesis? 


306  ANTiaUITY  OF  THE  EARTH. 

fleeter  of  Lord  Rosse,  and  by  others,  and  shown  to  be  clusters  o£ 
stars.  These  discoveries  have  somewhat  weakened  the  evidence 
in  support  of  the  hypothesis  ;  but,  on  the  other  hand,  the  discov- 
eries of  Kirkwood  in  respect  to  the  relations  between  the  num- 
ber of  rotations  of  the  planets  and  the  diameters  of  their  spheres 
of  attraction,  would  show  that,  at  some  remote  period,  there  must 
have  been  a  physical  connection  of  the  different  bodies  of  the  so- 
lar system ;  and  if  "  his  analogies,"  as  they  are  termed,  are  fully 
established,  they  will  offer  the  strongest  proof  hitherto  furnished 
of  the  former  nebulous  condition  of  the  universe. 


CHAPTER  X. 
ANTIQUITY  OF  THE  EARTH. 

THE  antiquity  of  the  earth  is  a  subject  which  has  excited  mucn 
interest  b9th  among  geologists  and  theologians.  The  idea  of  long 
periods  of  time  previous  to  the  introduction  of  man  has  been  sup- 
posed by  many  to  conflict  with  the  Mosaic  history.  Before  we 
attempt  to  reconcile  the  records  of  geology  with  this  history,  it 
is  desirable  to  establish,  by  physical  evidence,  the  great  age  of 
the  world.  We  have  already  given,  in  the  preceding  parts  of 
the  work,  the  principal  facts  which  are  the  basis  of  this  argument, 
and  it  only  remains  to  gather  into  one  view  the  chief  points  which 
are  relied  on  to  establish  the  truth  of  the  proposition, 

That  the  earth  existed  for  long  periods,  and  passed  through  many 
changes  previous  to  the  introduction  of  the  human  species. 

The  evidence  upon  which  the  argument  for  the  antiquity  of 
the  earth  is  based  is  derived  from  the  structure,  character,  and 
position  of  the  rocks,  the  remains  of  animals  and  plants,  and  the 
mutual  relations  of  the  organic  and  inorganic  portion  of  the  earth's 
crust. 

What  has  weakened  the  evidence  in  favor  of  the  nebular  hypothesis  ?  What 
has  strengthened  it  ?  What  is  the  object  of  this  chapter  ?  From  what  sources 
is  the  evidence  of  the  great  age  of  the  world  derived  ? 


ANTIQUITY    OF    THE    EARTH.  307 

SECTION  I.— THE  ANTIQUITY  OF  THE  EARTH,  AS  INFERRED  FROM  THE 
STRUCTURE,  COMPOSITION,  AND  POSITION  OF  THE  ROCKS. 

I.  Basis  of  the  Argument. — In  our  examination  of  the  rocks 
which  are  now  forming  at  the  bottom  of  lakes  and  the  ocean,  we 
nave  noticed  that  their  siructure  indicates  the  mode  of  their  for- 
mation.    They  are  arranged  in  regular  layers,  which  may  be 
easily  separated  in  one  direction,  and,  as  we  see  the  process  act- 
ually in  progress,  we  find  no  difficulty  in  understanding  it.     The 
sand,  mud,  and  organic  bodies  which  are  borne  from  the  conti- 
nents by  the  rivers  into  the  ocean  subside  to  the  bottom  in  thin 
layers,  inclosing  marine  animals  and  plants.     These  layers,  by 
means  of  the  mechanical  pressure  of  water,  and  by  the  chemical 
agency  of  lime  and  iron,  aided  sometimes  by  heat,  are  gradually 
consolidated.     In  many  cases  these  layers  have  been  broken  up 
and  variously  inclined  by  volcanic  agency. 

If  now  we  take  a  rock  thus  formed  and  compare  it  with  those 
rocks  which  we  have  described  as  stratified,  we  shall  notice  a 
very  great  similarity  of  structure.  The  resemblance  is  so  perfect 
in  many  cases,  that  it  would  be  difficult  to  decide  which  was 
formed  first.  The  legitimate  inference  is,  that  riot  only  the  rocks 
thus  compared,  but  the  whole  class  of  strata  which  possess  this 
structure,  wherever  they  may  be  found  on  the  surface  of  the  earth, 
have  been  formed  by  the  same  agencies  and  by  a  similar  pro- 
cess ;  that  is,  that  their  materials  were  brought  by  the  agency 
of  water  from  the  then  existing  continents,  and  deposited  in  lay 
ers  at  the  bottom  of  ancient  seas  and  lakes  ;  that  these  strata  have 
been  hardened  into  solid  rock,  and,  finally,  that  the  strata  have 
been  broken  and  tilted  up  on  their  edges  by  a  force  acting  from 
beneath,  or  by  the  agency  of  heat.  The  argument  is  based  on 
the  analogy  between  the  present  and  the  past  changes  in  the 
crust  of  the  globe. 

II.  Character  and  Position  of  the  Strata. — The  character  and 
position  of  these  strata  prove  that  a  series  of  successive  changes 
have  tat  en  place  which  require  long  periods  of  time. 

What  is  the  basis  of  the  argument  by  which  the  great  age  of  the  world  in 
proved  ?     From  what  is  the  first  argument  derived  ? 


308  ANTIQUITY    OF    THE    EARTH 

The  separate  layers  which  constitute  a  formation  in  each  of 
the  geological  epochs  are,  as  we  have  seen,  conformable  to  each 
other,  but  the  formations  themselves  are  often  inclined  or  uncon 
formable.  The  several  groups,  however,  always  maintain  the  same 
uniform  order  of  position.  The  Palaeozoic  rocks  in  the  United 
States,  from  the  Potsdam  sandstone,  the  base  of  the  Silurian  sys- 
tem, to  the  top  of  the  coal-beds,  are  generally  conformable  to 
each  other,  but  each  of  the  separate  formations  always  occupies 
the  same  relative  position. 

The  coal  strata  in  England  are  often  much  inclined,  and  strata 
of  sandstone  lie  directly  across  their  edges.  It  is  obvious,  there- 
fore, that  the  coal-beds  were  deposited  and  tilted  up  before  the 
sandstones  were  formed.  The  tertiary  of  the  London  and  Paris 
basins  is  found  in  basin-shaped  depressions  of  the  chalk,  and  lies 
unconformably  to  it.  In  penetrating  through  their  beds,  we  find 
London  clay,  plastic  clay,  chalk  and  green  sand,  and  this  order 
is  never  reversed  wherever  these  rocks  are  found  in  junction  on 
the  surface  of  the  earth.  The  tertiary  is  always  above  the  cre- 
taceous, and  never  below  it ;  the  cretaceous  above  the  oolitic, 
the  oolitic  above  the  liassic,  triassic,  &c.  The  position  of  each 
group  shows  one  uniform  order  of  formation,  and  this  indicates 
their  relative  age. 

This  conclusion  is  further  sustained  by  the  fact  that  the  rocks 
in  the  higher  groups  are  often  composed  in  part  of  fragments  of 
those  in  the  lower  groups.  Thus  the  lower  tertiary  beds  in  the 
London  and  Paris  basins  are  filled  with  pebbles  of  chalk.  The 
new  red  sandstone  of  the  Connecticut  River  valley  is  composed 
of  the  metamorphic  Silurian  rocks  of  Vermont.  The  conglome- 
rate rocks  are  composed  entirely  of  materials  derived  from  rocks 
which  occupy  a  lower  position,  and  examples  of  a  similar  char 
acter  are  found  throughout  the  strata,  all  tending  to  show  that 
the  group  which  is  lower  in  relative  position  has  been  formed  pre- 
vious to  the  one  which  lies  above  it. 

What  order  is  observed  among  the  several  formations?  Give  examples. 
By  what  is  the  relative  age  of  the  formations  indicated?  By  what  fact  is 
this  conclusion  confirmed? 


ANTIQUITY  OF  THE  EARTH.  309 

Observations  on  this  subject  have  been  conducted  with  the 
greatest  care  by  the  ablest  geologists  in  Europe  and  in  this  coun- 
trv,  and  this  uniform  order  of  arrangement  has  been  satisfactorily 
demonstrated. 

The  position  and  composition,  then,  of  the  stratified  rocks  re- 
quire a  series  of  successive  changes  in  the  materials  of  the  earth's 
crust.  This  fact  is  fatal  to  the  hypothesis  which  attributes  the 
formation  of  the  strata  to  sudden  and  simultaneous  deposition 
from  water  or  to  the  agency  of  deluges,  for  one  group  in  many 
cases  must  not  only  have  had  time  for  its  deposition,  but  also  to 
be  hardened  into  rock  from  the  condition  of  fine  sand  or  mud, 
then  to  be  elevated  and  exposed  to  the  agents  of  degradation  be- 
fore the  formation  of  succeeding  groups  could  have  commenced. 
Now  when  we  consider  the  fact  that  two  thirds  of  existing  con- 
tinents are  covered  with  stratified  rocks  to  a  depth  of  six  to  ten 
miles,  when,  from  their  structure,  composition,  and  position, _we 
are  compelled  to  believe  that  their  formation  must  have  proceeded 
gradually,  and  in  most  cases  in  tranquil  waters,  we  are  furnished 
with  a  powerful  argument  in  support  of  the  proposition  that  the 
series  of  changes  required  for  their  deposition  must  have  extend- 
ed through  long  periods  of  time. 

III.  The  relation  of  the  unstratified  or  igneous  rocks  to  the 
stratified  strengthens  the  above  conclusion.  We  have  seen  that 
the  igneous  rocks  have  penetrated  the  strata  at  different  and  dis- 
tant periods  in  every  direction,  lifting  them  up,  and  plicating 
them  in  such  manner  as  to  prove  a  series  of  successive  changes 
(see  page  302).  "  Each  individual  movement  has  contributed  its 
share  toward  the  final  object  of  conducting  the  molten  materials 
of  an  uninhabitable  planet  through  long  successions  of  change 
and  of  convulsive  movements,  to  a  tranquil  state  of  equilibrium, 
in  which  it  has  become  the  convenient  and  delightful  habitation 
of  man,  and  of  the  multitudes  of  terrestrial  creatures  that  are  his 
fellow- tenants,  of  its  actual  surface." — Buckland. 

Where  have  observations  been  conducted,  and  with  what  result  ?  To  what 
hypothesis  are  these  facts  opposed?  What  is' the  conclusion?  What  other 
tacts  confirm  this  conclusion  ? 


310  ANTIQUITY    OF    THE    EARTH 

SECTION  II.— THE  ANTIQUITY  OF  THE  EARTH  AS  INFERRED  FROM  THE  RE- 
MAINS OF  ORGANIZED  BEINGS. 

The  character  and  position  of  the  mineral  masses  which  con- 
stitute the  crust  of  the  earth  render  the  supposition  of  its  having 
been  molded  into  its  present  form  in  six  days,  or  in  6000  years, 
in  the  highest  degree  improbable. 

But  when  we  examine  the  remains  of  animals  and  plants,  and 
notice  their  character  and  position,  we  derive  an  argument  for 
the  antiquity  of  the  earth  which  is  wholly  unanswerable,  while 
the  opposite  doctrine  is  rendered  not  only  incredible  but  absurd. 
No  honest  mind  can  believe  it,  unless  it  is  prepared  to  believe 
that  the  Deity  has  furnished  us  with  reasoning  powers  for  the 
purpose  of  deceiving  us. 

I.  The  distribution  and  abundance  of  the  remains  of  organiza- 
tion in  the  earth's  crust  evince  a  high  antiquity  of  the  earth. 

We  have  seen  that  the  remains  of  animals  and  of  plants  are 
found  in  all  the  stratified  rocks  from  the  base  of  the  Silurian  sys 
tern  through  all  the  successive  deposits  up  to  the  present  period 

Each  group  contains  a  peculiar  type.  The  families  and  genera 
often  extend  through  two  or  more  formations,  but  the  species  are 
generally  confined  to  a  single  geological  period.  As  the  condi- 
tion of  the  earth  was  changed,  and  the  old  species  died  out,  either 
new  species  of  the  same  genera  were  introduced,  or  an  entirely 
new  race  were  brought  upon  the  stage  of  life. 

In  the  older  rocks,  the  Silurian,  the  animals  and  plants  be- 
longed to  the  lower  types  of  organization.  The  plants  were 
mostly  marine,  and  the  mollusca,  radiata,  articulata,  and  a  few 
fishes  and  reptiles  were  the  only  types  of  animal  existence. 

As  we  rise  in  the  series  fishes  are  more  abundant,  and  reptiles 
make  their  appearance  in  greater  numbers  near  the  close  of  the 
Palaeozoic  period.  In  the  trias  we  have  the  first  evidence  of  the 
existence  of  birds,  in  the  numerous  impressions  of  their  feet  upon 

What  is  said  of  the  argument  derived  from  the  remains  of  organization  ?  of 
the  distribution  of  fossils  1  What  types  prevailed  in  the  lower  rocks  1  What 
changes  are  observed  as  we  proceed  from  the  earlier  to  the  later  geological 
times  *  When  do  reptiles  make  their  appearance  1  birds  1 


ANTIQUITY  OP  THE  EARTH.  311 

sandstones,  as  Aose  of  the  Connecticut  River  valley.  The  sau- 
rian tribes,  of  singular  and  monstrous  proportions,  succeed  the 
birds  in  the  lias,  and  extend  to  the  chalk. 

At  the  close  of  the  cretaceous  period  the  ancient  races  were 
all  exterminated,  and,  with  the  commencement  of  the  tertiary 
mammals,  with  But  three  exceptions  (page  235),  were  for  the  first 
time  introduced.  Cetaceans,  pachydermata,  and  carnivora,  were 
the  prevailing  forms.  They  were  allied  to  existing  families,  but 
the  species  are  all  extinct.  In  this  general  distribution  we  may 
discover  a  succession  of  animal  forms  which  were  adapted  to  the 
condition  of  the  mineral  masses,  and  which,  in  their  character, 
gradually  become  more  and  more  allied  to  existing  species. 

The  same  succession  in  the  forms  of  vegetable  life  may  be  ob- 
served in  the  successive  periods  of  the  earth's  history. 

As  these  fossil  bodies  are  found  in  all  parts  of  the  rocky  strata, 
they  reveal  to  us  the  conditions  of  the  earth  when  they  existed 
as  living  creatures,  and  the  changes  by  which  they  were  entomb- 
ed in  its  rocky  beds.  Their  character  and  position  form  the  most 
perfect  chronological  charts  by  which  to  determine  the  great  age 
of  the  world. 

The  abundance  of  these  remains  sets  aside  every  hypothesis 
which  would  account  for  their  existence  by  any  other  processes 
than  those  which  we  have  described.  "  It  must  appear  almost 
incredible  to  those  who  have  not  minutely  attended  to  natural 
phenomena,  that  the  microscopic  examination  of  a  mass  of  rude 
and  lifeless  limestone  should  often  disclose  the  curious  fact  that 
large  proportions  of  its  substance  have  once  formed  parts  of  liv- 
ing bodies.  It  is  surprising  to  consider  that  the  walls  of  our 
houses  are  sometimes  composed  of  little  else  than  comminuted 
shells,  that  were  once  the  domicile  of  other  animals  at  the  bottom 
of  ancient  seas  and  lakes.  It  is  marvelous  that  mankind  should 
have  gone  on  for  so  many  centuries  in  ignorance  of  the  fact  which 
is  now  so  fully  demonstrated,  that  no  small  part  of  the  present 
surface  of  the  earth  is  derived  from  the  remains  of  animals  which 

vVhen  do  saurians  make  their  appearance  1  mammals  ?  What  succession  iu 
the  types  of  vegetable  life  1  What  is  said  of  the  abundance  of  these  remains  T 


312  ANTiaUITY  OF  THE  EARTH. 

constituted  the  population  of  ancient  seas.  Many  extensive 
plains  and  massive  mountains  form,  as  it  were,  the  great  charnel' 
house  of  preceding  generations,  in  which  the  petrified  exuvia  of 
extinct  races  of  animals  and  plants  are  piled  into  stupendous 
monuments  of  the  operations  of  life  and  death  during  almost  im- 
measurable periods  of  past  time." — Buckland. 

II.  But  the  argument  for  the  antiquity  of  the  earth,  as  inferred 
from  the  remains  of  organization,  may  be  presented  with  greater 
distinctness  by  specific  examples.  The  vegetables  of  the  carbo- 
niferous period  furnish  the  most  convincing  proof  of  the  great 
age  of  the  world. 

1.  This  evidence  appears  in  the  peculiar  character  of  the  veg- 
etation and  present  position  of  the  fossil  trees  (p.  264),  indicating  a 
condition  of  the  earth  so  unlike  the  present,  that  we  are  forced 
to   believe  that  a  long  period   of  time  was  consumed  in  their 
growth  and  deposition  in  the  strata  of  the  earth.     Most  of  them 
ar^  tropical  plants,  and  yet  they  are  buried  in  the  rocks  beneath 
the  polar  snows.*     Their  position  often  shows  that  they  grew  in 
the  localities  where  they  are  found,  and  were  not  drifted  from 
warmer  climes.     Large  trees  are  found  buried  1000  feet  beneath 
the  earth's  surface,  and  geologically  they  are  at  the  depth  of  sev- 
eral miles.     How  can  their  position  be  accounted  for  ?     It  is  pos- 
sible that  a  few  trees  may  have  fallen  into  rents  of  the  earth's 
crust  produced  by  volcanic  agency  ;  a  larger  number  might  have 
been  submerged  by  a  sinking  down  of  the  earth's  crust  during 
earthquakes,  covered  up,  and  then  elevated  again  by  the  same 
force.     In  thes.e  cases  we  should  expect  to  find  them  of  the  same 
species  with  existing  plants,  but  this  is  not  the  fact.     The  coal 
plants  are  all  extinct  species. 

2.  But  when  we  examine  the  character  and  position  of  the  coal- 
beds,  and  the  extent  of  the  coal-fields,  such  an  hypothesis  is  wholly 

*  Vegetables  are  found  in  the  rocks  as  far  north  as  Baffin's  Bay  and  Mel- 
ville Island,  in  latitude  75  degrees. 

What  is  said  of  the  character  of  the  vegetables  of  the  carboniferous  period  1 
What  does  their  position  in  the  rocks  show?  How  came  they  to  be  buried 
in  the  rocks  ?  What  hypothesis  is  suggested  ? 


ANTIQUITY  OF  THE  EARTH.  313 

inadequate  to  explain  the  phenomena.  The  Derbyshire  coal- 
field, in  England,  furnishes  an  example  in  point.  Immediately 
under  the  coal  are  strata  of  shale  from  300  to  600  feet  in  depth, 
then  strata  of  the  mill-stone  grit  filled  with  the  remains  of  vege- 
tables. Above  the  grit  are  regular  coal  strata,  consisting  of  sand- 
stones in  thin  sheets,  iron  stones  containing  numerous  fossils,  and 
soft  argillaceous  beds  called  shale.  Two  strata  contain  fresh- 
water shells.  The  whole  thickness  is  3930  feet.  The  series  in 
eludes  thirty  different  strata  of  coal,  varying  from  6  inches  to  11 
feet  in  thickness.  The  whole  depth  of  the  coal  seams  is  78  feet. 

The  Scotch  coal-field  in  some  places  consists  of  10  beds,  whose 
united  thickness  is  100  feet.  The  South  Welsh  coal  basin  con- 
tains 23  beds  of  coal,  whose  total  thickness  is  93  feet.  These 
fields  extend  over  hundreds  of  square  miles. 

But  the  largest  coal-field  in  the  world  is  in  the  United  States. 
The  great  Appalachian  coal  formation  extends  over  a  portion  of 
tbe  States  of  Pennsylvania,  Maryland,  Virginia,  Alabama,  Ten- 
nessee, Kentucky,  and  Ohio.  "  Its  length  from  northeast  to 
southwest  is  rather  more  than  720  miles,  and  its  greatest  width 
about  180  miles.  Upon  a  moderate  estimate,  its  superficial  area 
amounts  to  63,000  square  miles." — H.  D.  Rogers. 

The  coal  strata  consist  of  alternate  layers  of  limestone,  sand- 
stone, shales,  and  seams  of  coal,  and  are  from  a  few  hundred  to 
three  thousand  feet  in  thickness.  The  coal  itself  appears  to  have 
been  formed  mostly  from  some  peat-creating  plant,  which  grew 
on  extensive  marshes  upon  the  borders  of  the  sea,  as  very  few 
large  trees  are  found  in  the  coal-beds,  although  their  leaves  and 
branches  are  so  numerous  as  to  lead  to  the  inference  that  extens- 
ive forests  flourished  upon  the  margins  of  those  "  vast  marine 
savannahs." 

Now  the  quantity  of  coal  in  all  the  coal-fields  in  the  world  has 
been  estimated  at  five  thousand  billions  of  tons,  and  this  immense 

What  objections  to  this  hypothesis?  What  examples  are  mentioned? 
What  do  these  examples  prove  ?  What  is  said  of  the  extent  of  the  Appala- 
chian coal-field  ?  of  the  character  of  coal  ?  What  estimate  has  been  made  of 
the  quantity  of  coal  in  the  world? 

o 


314  ANTIQUITY  OF  THE  EARTH. 

quantity  of  carbon  must  have  been  abstracted  froir  the  atmos- 
phere by  the  process  of  vegetation,  for  by  microscopical  examina- 
tions of  thin  slices  of  coal  the  vegetable  structure  has  been  so 
distinctly  seen,  that  in  many  cases  the  families  and  species  of 
plants  which  formed  the  coal  have  been  determined. 

The  vegetables,  then,  for  each  of  the  30  or  60  seams  in  the 
several  coal-fields,  must  have  had  time  to  grow,  just  as  plants  grow 
at  the  present  day — this  is  proved  by  the  concentric  rings  of  an- 
nual increase — time  to  be  torn  away  by  storms  and  sea-waves, 
produced,  no  doubt,  by  earthquake-pulsations,  which  elevated  and 
platted  the  strata,  and  brought  the  sea  ooze  or  mud  over  the  peat 
marshes ;  there  must  have  been  time  for  the  vegetable  matter  thus 
covered  with  mud  to  be  carbonized  (which  is  a  slow  process),  and 
after  each  bed  was  thus  slowly  formed,  there  must  have  been 
time  for  the  whole  to  have  been  broken  up  and  elevated  by  vol- 
canic agency  to  its  present  position.  Considering  the  character 
of  the  coal  strata  and  the  extent  of  the  coal-fields,  is  it  possible  to 
believe  that  all  has  been  deposited  since  the  creation  of  man  ? 

It  should  be  observed  that,  above  the  coal  strata,  the  remains 
of  vegetables  exist  in  all  the  rocks,  but  most  of  the  species  are 
different  from  those  of  the  coal  period.  In  the  tertiary  beds  of 
Germany  are  found  extensive  beds  of  brown  coal,  containing 
trees  from  9  to  13  feet  in  diameter,  in  one  of  which  there  were 
counted  792  rings  of  annual  increase.  The  tree  must  have  re- 
quired nearly  eight  centuries  for  its  growth,  and  afterward  con- 
verted into  coal. 

But  if  any  are  disposed  to  doubt  the  evidence  of  antiquity  de- 
rived from  these  fossil  bodies,  let  them  go  to  Senegal,  in  Africa, 
and  examine  the  baobab-tree  (Adansonia  digitata),  which  is  30 
feet  in  diameter,  and  has  been  estimated  by  the  concentric  ring? 
of  annual  increase,  to  be  five  thousand  one  hundred  and  fifty 
years  old ;  and,  if  they  are  still  in  doubt,  let  them  visit  Central 

Whence  has  the  coal  been  derived?  What  proof  of  this?  Mention  the 
changes  to  which  the  coal  strata  must  have  been  subjected.  What  is  the  con 
elusion  from  this  examination?  In  what  other  rocks  are  the  remains  of  veg* 
dtahAes  found  ?  What  is  said  of  the  size  and  age  of  existing  trees  ? 


ANTiaUITY  OF  THE  EARTH.  315 

America,  and  notice  the  celebrated  Toxodiura,  of  Chapultepec 
which  is  117  feet  in  circumference,  and  has  been  estimated  by 
De  Candolle  to  be  still  more  aged.  Professor  Henslow  estimates 
its  longevity  from  4000  to  6000  years.  Then  reflect  that  these 
antediluvian  trees,  that  flourished  in  the  days  of  the  patriarchs — 
that  were  a  thousand  years  old  when  Noah  was  born — that  were 
cotemporary  with  our  First  Parents — reflect  that  these  vener- 
able trees  stand  upon  the.  loose  soils  which  overlie  all  the  pre- 
ceding geological  formations  with  their  organic  contents.  The 
soil  was  formed  there  before  the  trees  were  planted,  and,  before 
the  soil  was  formed,  the  entire  series  of  rocks  were  deposited, 
and  similar  trees,  in  countless  numbers,  had  their  long  periods  of 
growth  and  decay. 

III.  We  might,  if  our  limits  would  permit,  bring  many  specific 
examples  of  the  character  and  position  of  the  fossil  animals, 
which  would  fully  confirm  the  truth  of  the  proposition  we  are 
considering.  Few  are  aware  of  the  immense  numbers  and  of 
the  peculiar  character  of  the  animal  remains  which  modern  re- 
searches have  brought  to  light.  Their  existence  in  the  rocks  is 
of  itself  ample  demonstration  of  a  higher  antiquity  than  is  gener- 
ally assigned  to  the  earth. 

The  earliest  animals  were  principally  radiata,  mollusca,  and 
fishes.  They  prevailed  almost  exclusively  until  near  the  close 
of  the  carboniferous  period,  when  we  find  the  first  evidence  of  the* 
existence  of  reptiles.  Throughout  the  Paleozoic  deposits,  their 
remains  form  a  considerable  portion  of  many  strata  of  rocks. 

With  the  triassic  period  birds  were,  for  the  first  time,  intro- 
duced, and  reptiles  became  more  numerous.  The  evidence  of 
the  existence  of  these  animals  is  presented  to  us  by  their  tracks 
and  fecal  remains.  These  have  already  been  described.  Their 
distribution  through  the  strata,  their  gigantic  dimensions,  indi- 
cate not  only  conditions  of  the  earth  unlike  the  present,  but  vast 
periods  of  time  during  which  they  flourished.  Having  left  the 

What  changes  occurred  before  those  trees  existed  ?  What  is  said  of  th« 
character  and  abundance  of  animal  remains  ?  What  was  the  character  of  the 
»>arliest  animals  ? 


ANTIQUITY    OF    THE    EARTH. 

indisputable  marks  of  their  existence  in  the  rocks,  they  were,  at 
the  close  of  this  period,  all  exterminated,  and  were  succeeded  in 
the  next  group  by  lizards,  saurians,  and  tortoises. 

From  the  commencement  of  the  liassic  down  to  the  close  of 
the  cretaceous  period,  we  find  some  of  the  most  extraordinary 
organic  forms  which  have  ever  existed ;  so  unlike  to  preceding 
types,  and  to  those  that  succeeded,  as  to  impress  upon  us  the 
belief  of  a  peculiar  condition  of  the  earth's  surface  during  the 
period  of  their  existence.  The  remains  of  huge  saurians,  of  gi- 
gantic reptiles,  and  of  flying  lizards,  are  distributed  through  stra- 
ta more  than  4000  feet  in  thickness,  and  are  associated  with  in- 
numerable generations  of  other  inhabitants  that  "  swam  in  the 
waters  or  basked  on  the  shores  of  the  primeval  lakes  and  seas." 
But,  in  one  of  those  successive  changes  which  had  swept  away 
preceding  races,  they  in  turn  were  all  destroyed,  and  were  suc- 
ceeded by  entirely  new  and  distinct  types  of  animals  more  nearly 
related  to  existing  races. 

During  the  tertiary  period  the  land  quadrupeds  (Mammalia] 
were  introduced  in  great  numbers,  and  continued  to  flourish 
down  to  the  close  of  the  Pleistocene,  when  the  species  were 
mostly  destroyed. 

Last  of  all,  in  the  most  recent  deposits  are  found  the  remains 
of  man  and  his  cotemporary  races  ;  and  the  fact 'that  human  rel- 
ics are  not  found  lower  in  the  rocks  is  positive  proof  that  all  those 
other  races  lived  and  passed  away  previous  to  the  appearance  of 
man  on  earth. 

It  appears,  then,  as  the  result  of  geological  investigations,  that 
innumerable  generations  of  organized  beings  have  peopled  the 
earth  during  its  past  history.  In  such  countless  numbers,  in  such 
infinite  variety,  in  such  great  abundance  are  their  remains  stored 
in  the  rocky  strata,  forming  almost  the  entire  soil  on  which  we 
tread,  that  we  may  properly  inquire  with  Young  for  the  "  dust 
that  has  not  been  alive  ;"  but  it  is  impossible  to  believe  that  they 
have  all  lived  within  the  last  6000  years. 

What  types  succeeded  the  earliest  animals  ?  What  is  the  evidence  which 
the  successive  races  furnish  of  long  periods  of  time  ?  What  conclusion  is  drawn 
from  the  examination  of  animal  remains  ? 


ANTIQUITY    OF    THE    EARTH.  317 

SECTION  III.— ANTIQUITY  OF  THE  EARTH  AS  INFERRED  FROM  THE  MUTUAL 
RELATIONS  OF  THE  ORGANIC  AND  INORGANIC  PORTIONS  OF  THE  EARTH'S 
CRUST. 

If  now  we  combine  the  two  branches  of  this  argument,  viz., 
that  derived  from  the  remains  of  organic  beings,  and  that  from 
the  structure  and  position  of  the  rocks,  and  notice  the  changes 
which  must  have  been  effected  by  the  three  agents,  water,  fire, 
and  vitality,  we  can  not  fail  to  perceive  that  the  physical  evidence 
of  the  great  age  of  the  world  is  perfectly  conclusive.  These  re- 
lations have  been  partially  presented  in  the  preceding  sections. 
Let  us  select  a  few  examples. 

I.  In  Auvergne,  in  central  France,  there  occur  a  series  of  the 
older  tertiary  deposits,  which  of  themselves  appear  to  settle  the 
question  of  the  age  of  the  world.  This  district  embraces  an  area 
of  1600  square  miles  (see  page  194).  It  consists  of  a  great  basin 
filled  with  fresh-water  limestones,  sandstones,  clays,  marls,  and 
volcanic  products,  to  the  depth  of  from  700  to  1000  feet.  The 
strata  rest  on  the  primitive  rocks,  which  must  have  been  elevated 
from  the  bed  of  the  primeval  ocean,  forming  large  fresh-water 
lakes,  before  the  tertiary  deposits  could  have  commenced. 

In  some  places  the  limestones  and  marls  alternate  with  each 
other.  The  marls  consist  of  thin  leaves  about  the  thickness  of 
paper.  Each  leaf  contains  multitudes  of  the  crustaceous  cover- 
ings of  the  cypris  and  of  small  shells. 

The  cypris  moults  its  shell  annually,  and,  as  the  coverings  fall 
down  upon  the  bottom  of  the  lake,  they  are  covered  with  mud, 
and  become  cemented  into  sheets.  Each  marl  leaf  was  then  just 
one  year  in  forming.  The  leaves  are  not  more  than  ^th  of  an 
inch  in  thickness.  For  the  deposition,  then,  of  one  inch,  it  re- 
quired 20  years  ;  for  one  foot,  240  years.  Now  the  vertical  thick 
ness  of  the  marl  strata  is  from  60  to  100  feet,  and  this  would  re- 
quire from  14,000  to  24,000  years  !  The  other  deposits  were 

In  what  way  is  the  argument  for  the  antiquity  of  the  earth  presented  in  sec- 
tion third  ?  What  facts  in  Auvergne  evince  a  high  antiquity  of  the  earth  ? 
Describe  the  manner  in  which  the  marl  beds  were  formed.  How  long  a  tim« 
is  required  to  form  them  ? 


318  ANTIQUITY  OF  THE  EARTH. 

not,  probably,  formed  in  a  more  rapid  manner  than  the  marls  aa 
they  are  filled  with  the  remains  cf  innumerable  shell-fishes,  and 
the  bones  of  land  quadrupeds. 

In  the  upper  beds  are  found  strata  of  volcanic  ashes,  which  in- 
dicate the  commencement  of  the  volcanic  period  of  this  region, 
during  which  more  than  60  volcanic  mountains  were  built  up, 
and  now  remain  with  their  craters  several  hundred  feet  in  depth. 
The  lava  currents  are  easily  traced  from  their  vents  in  different 
directions,  passing  across  the  streams,  forming  new  systems  of 
lakes,  and  changing  the  whole  face  of  the  country. 

t)uring  this  period  the  mastodon,  the  elephant,  and  large  her- 
bifera  were  created,  and  inhabited  the  neighboring  land.  They 
were  covered  up  by  showers  of  volcanic  ashes  and  lava  streams, 
or  drifted  into  the  lakes,  where  their  bones  are  preserved  in  a 
state  of  great  perfection.  After  a  long  period,  the  volcanoes 
cease  their  activity,  and  the  new  lakes  are  filled  with  fresh- water 
deposits.  Bears,  hyenas,  and  various  carnivorous  tribes  are  asso- 
ciated with  the  mastodon  and  elephant,  and,  finally,  these  are  all 
exterminated,  and  the  existing  races  succeeded.  If  now  we  es- 
timate these  changes  by  the  present  operation  of  natural  laws,  it 
must  have  required  millions  of  years  for  them  to  have  taken 
place. 

II.  But  in  other  parts  of  the  earth,  as  in  the  north  of  Italy  and 
Germany,  extensive  deposits  occur  which  are  more  recent  than 
the  marls  of  Auvergne ;  and  if  we  examine  parts  of  Sicily  south 
of  JStna,  we  shall  notice  strata,  2000  feet  in  thickness,  still  more 
recent.  These  rocks  are  so  filled  with  shell-fishes  as  to  show 
that  the  whole  was  beneath  the  sea  during  their  formation,  arid 
that  the  island  was  not  elevated  until  the  last  shell  was  deposit- 
ed. If  now  we  pass  to  JEtna,  we  may  notice  that  the  whole 
mountain,  which  is  ninety  miles  in  circumference,  and  eleven 
thousand  feet  in  height,  has  been  sent  up  since  the  deposits  south 

What  other  changes  occurred  in  the  rnarl  beds  ?  What  animals  existed  ? 
What  has  become  of  them?  What  other  deposits  of  this  period  are  referred 
to  as  indicating  long  periods  of  time  ?  What  is  said  of  jEtua,  and  what  proof 
of  antiquity  derived  from  its  character  and  history  ? 


ANTIQUITY  OF  THE  EARTH.  319 

of  the  mountain  were  formed.  And  yet  the  mountain  has  a  ven- 
erable age.  It  has  existed  nearly  as  at  the  present  time  since 
history  gives  us  any  account  of  it.  But  "  of  the  eighty  most  con- 
spicuous cones  which  adorn  its  flanks,  only  one  of  the  largest, 
Monti  Rossi,  has  been  produced  since  the  times  of  authentic  his- 
tory."— Lyell.  If  we  were  to  remove  these  cones,  it  would  but 
slightly  diminish  the  height  of  the  mountain,  and  we  should  doubt- 
less find  a  similar  series  of  cones  beneath.  If,  then,  but  one  cone 
has  been  formed  within  a  period  of  2000  years — if,  on  this  sup- 
position, 1,600,000  years  were  consumed  in  the  formation  of  the 
SO  cones — who  will  undertake  to  measure  the  time  which  trans- 
pired during  the  formation  of  the  whole  mountain  ? 

III.  Passing  from  the  tertiary  group  to  the  older  formations,  we 
find  first  the  chalk,  which  is  about  1000  feet  in  depth,  and  is  com- 
posed of  small  shells  and  corals ;  these  must  have  been  formed 
by  animals  previous  to  their  deposition  in  regular  strata.     Under 
the  chalk  are  beds  of  green  sand  480  feet  in  depth,  and,  having 
penetrated  through  these,  we  come  to  the  Wealden,  900  feet  in 
vertical  depth.     The  latter  is  a  fresh-water  deposit,  living  be- 
tween strata  which  were  formed  beneath   salt  water.     In  this 
group  we  notice  the  remains  of  whole  forests,  the  trees  standing 
in  the  position  in  which  they  grew,  as  in  the  "  Portland  dirt  bed." 
Here  the  land  must  have  been  above  the  water  a  sufficient  time 
for  trees  to  grow  two,  three,  and  four  feet  in  diameter,  then  to 
have  been  submerged,  and  upon  it  all  the  other  groups  deposited, 
arid,  finally,  the  whole  must  have  been  elevated  to  its  present 
position  several  hundred  feet  above  the  level  of  the  sea. 

IV.  If  any  still  doubt  the  great  age  of  the  world,  let  them  pen- 
etrate still  deeper  into  the  oolitic  and  liassic  groups,  nearly  3000 
feet  through  series  of  strata  filled  with  the  remains  of  saurians, 
pterodactyls,  and  huge  iguanodons,  and  in  the  same  manner  con- 
tinue their  observations  through  the  triassic  system  to  the  depth 
of  1500  feet,  and  become  acquainted  with  the  gigantic  frogs  and 
birds  that  left  their  footprints  on  the  now  hardened  sandstones. 

What  is  the  argument  derived  from  the  cretaceous  rocks  ?  the  Wealden  f 
the  oolitic  and  liassic  formations  ?  the  red  sandstone  ? 


320  ANTiaUITY  OF  THE  EARTH. 

"  Solving  a  problem, 
Man  never  has  to  leave  a  trace  on  earth 
Too  deep  for  time  and  fate  to  wear  away." 

Thence  proceed  to  the  coal-beds  and  view  the  ancient  forests 
which  supplied  the  materials  for  fossil  coal,  10,000  feet  deeper; 
thence  downward  three  miles  to  the  base  of  the  Potsdam  sand- 
stone, until  all  traces  of  organization  disappear,  from  which  poini 
they  may  descend  to  unknown  depths,  until  they  reach  the  orig 
inal  igneous  rocks  and  the  internal  fires.  And  if  these  observa 
tions  do  not  convince  them,  then  leave  all  these  stupendous  mon 
uments  of  antiquity,  and  come  down  to  modern  times,  to  the  for 
mation  of  terraced  valleys  and  coral  islands,  processes  which  are 
now  in  progress,  and  not,  therefore,  liable  to  deceive  them. 

V.  The  terraces  upon  the  river  valleys  have  evidently  resulted 
from  the  erosive  action  of  the  rivers  by  which  their  beds  have 
been  lowered.     Three  terraces  or  more  often  occur  one  above  the 
other.     Cities  have  been  built  upon  the  lowest  of  these  terraces 
for  more  than  2000  years,  during  which  period  the  action  of  tho 
streams  has  not  lowered  their  bottoms  but  a  few  feet  or  inches. 
The  time  required  for  rivers  thus  to  lower  their  beds  40,  50,  and 
60  feet,  must  have  been  more  than  6000  or  10,000  years.     In 
many  places  the  streams  have  cut  through  rocks  to  a  great  depth, 
as  the  Niagara  River,  which  also  proves  that  the  action  must  have 
been  long  continued. 

VI.  Many  of  the  coral  islands  indicate  very  .long  periods  of 
time.     We  have  described  (p.  78)  the  manner  in  which  these 
islands  have  been  formed.     Their  exact  rate  of  increase  is  not 
known,  but,  from  all  the  observations  which  have  been  made,  it 
is  exceedingly  slow. 

Ehrenberg,  who  has  examined  the  corals  of  the  Red  Sea, 
doubts  whether  channels  and  harbors  have  been  filled  by  these 
animals  during  the  historical  period.  The  single  corals  which 
he  saw  of  a  globular  form,  and  about  nine  feet  in  diameter,  he 

What  is  the  argument  derived  from  the  coal  and  rocks  below  ?  What  evi- 
dence is  furnished  by  terraces  and  channels  ?  What  evidence  of  age  do  tho 
coral  islands  furnish  ? 


ANTIQUITY    OF    THE    EARTH.  321 

supposes  might  have  been  seen  by  Pharaoh  in  nearly  the  same 
state  as  at  present.  If  they  increased  half  an  inch  in  a  year,  it 
would  take  6000  years  to  build  a  reef  250  feet  in  height ;  but  many 
of  them  are  much  thicker,  for  outside  of  the  reef  the  waters  be- 
come suddenly  very  deep,  "  no  soundings  having  been  obtained 
at  the  depth  of  150  fathoms,"  even  in  the  channels  which  lead  into 
the  lagoons. 

VII.  Each  of  the  several  groups  of  rocks  which  form  the  crust 
of  the  earth  affords  ample  proof  of  the  great  age  of  the  world;  but 
when  we  take  into  view  the  whole  series  of  changes,  organic  and 
inorganic,  the  argument  for  the  antiquity  of  the  world  is  so  per- 
fectly overwhelming,  that  those  who  have  carefully  attended  to 
the  evidence  on  which  it  is  based  are  not  only  convinced  of  its 
truth,  but  are  unable  to  express  by  numbers  the  long  periods 
which  must  have  passed  since  the  first  creation.  The  exact  age 
of  the  world  can  not  be  determined;  but,  to  aid  our  conceptions, 
we  may  perhaps  be  allowed  to  make  a  few  numerical  calculations. 
These  estimates  must  be  based  upon  the  rate  at  which  rocks  are 
now  forming  in  lakes  and  seas.  The  observations  on  this  subject 
are  few,  but  it  is  said  that  the  lakes  of  Scotland  have  shoaled 
about  a  foot  in  two  hundred  years,  and  that  the  mud  which  the 
rivers  transport  would  not  more  than  raise  the  general  floor  of  the 
ocean  one  foot  in  a  thousand  years.  On  this  basis,  if  we  take  the 
estimated  depth  of  the  Silurian  rocks  (p.  121)  at  8700  feet,  their 
deposition  would  require  a  period  of  8,700,000  years.  The  old 
red  sandstone,  or  Devonian  system,  estimated  at  10,000  feet, 
would  consume  10,000,000  years.  The  carboniferous  system  is 
estimated  also  at  10,000  feet,  and,  regarding  the  deposits  as  made 
in  lakes,  they  would  require  2,000,000  years. 
The  Permean  system  (oceanic)  800  feet  .  .  800,000  years. 
"  Triassic  "  900  "  .  .  900,000  " 

"     Liassic  "  "  700    "     .     .     700,000       " 

"     Oolitic  "  "          1400     "     .     .  1,400,000       " 

What  effect  is  produced  upon  those  who  carefully  examine  the  evidences 
o*  age  ?  Can  the  exact  age  of  the  world  be  determined  ?  In  what  way  may 
cur  conceptions  be  aided  ?  •  Upon  what  must  the  estimates  bo  based  ? 

02 


322  ANTiaUITY  OP  THE  EARTH. 

The  Wealden  system  (lake  dep.)     900  feet     .      180,000  years. 
"     Cretaceous   "      (oceanic)      1480    "        .  1,480,000      " 
"     Tertiary        "      (lake  dep.)  3500    "       .      700,000      " 
The  average  thickness  of  the  whole  strata  has  been  estimated 
at  10  miles.     On  this  supposition  it  would  require,  at  the  present 
rate  of  lake  deposits,  12,560,000  years;  but  if  the  rate  of  oceanic 
deposits  is  taken  as  a  standard  of  comparison,  they  must  have 
occupied  a  period  of  52,800,000  years  ! 

These  estimates  may  serve  to  give  us  some  definite  impression 
of  the  great  age  of  the  world,  and  yet  it  is  evident  that  they  do 
vast  injustice  to  the  antiquity  of  our  venerable  planet.  Astrono- 
mers tell  us  that  the  telescope  reveals  the  existence  of  stars  so 
deeply  sunk  in  space,  that  light  moving  at  the  rate  of  twelve  mil- 
lion of  miles  in  one  minute  would  be  half  a  million  of  years  in 
reaching  the  earth,  and  if  these  stars  were  blotted  from  the  face 
of  the  heavens  they  would  be  seen  for  half  a  million  of  years 
to  come.  It  is  not  improbable,  therefore,  that  our  earth,  the 
whole  universe  around  us,  is  many  million  times  older  than 
would  be  inferred  by  these  calculations. 

At  what  point  in  the  past  eternity  this  mighty  system  was  called 
into  being  we  can  not  determine,  nor  can  we  know  whether  at 
any  time  in  the  future  it  may  be  blotted  out. 

We  should  infer,  however,  from  the  history  of  the  past,  that 
oir  earth  is  destined  to  pass  through  other  changes  which  will 
i  Keep  away  the  existing  races,  and,  if  man  be  not  the  highest 
possible  type  of  physical  existence,  that  the  renovated  earth  will 
be  peopled  by  new  and  more  wonderful  forms  of  organic  beings, 
who  will  be  endowed  with  more  exalted,  intellectual,  and  moral 
powers. 

How  rapidly  do  rocks  form  in  lakes?  in  the  ocean?  On  these  data,  what 
length  of  time  was  occupied  in  the  deposition  of  the  several  classes  of  rocks  1 
How  long  time  for  the  whole  class  of  stratified  rocks  ?  Do  these  estimates 
truly  represent  the  actual  age  of  the  world?  F'om  the  history  of  the  past, 
what  clianges  are  to  be  expected  1 


ANTIQUITY    OF    THE    EARTH.  323 

SECTION  IV.— OBJECTIONS  TO  THE  ANTIQUITY  OF  THE  EARTH  CONSIDERED, 

I.  In  order  to  set  aside  the  evidence  which  the  rocks  afford  of 
the  great  age  of  the  world,  it  has  been  urged  that  the  agents  of 
nature  may  have  operated  with  much  greater  energy  in  the  ear- 
lier than  in  the  later  periods  of  the  earth's  history ;  and  that  the 
strata,  with  their  imbedded  fossils,  were  produced  between  Adam 
and  Noah,  and  chiefly  by  the  waters  of  the  deluge. 

This  hypothesis  requires  so  great  activity  of  the  agents  con- 
cerned in  the  production  of  animals  and  plants,  as  well  as  of  those 
by  which  the  rocks  were  formed,  that  there  are  no  analogies 
founded  upon  the  present  operation  of  physical  laws  to  sustain 
it.  The  only  question  is,  whether  there  are  good  and  substan- 
tial reasons  against  it.  From  the  many  reasons  which  oppose 
this  theory,  a  few  only  are  needed. 

1.  Many  of  the  fossil  trees  have  the  concentric  rings  of  annual 
growth,  and  these  yearly  additions  are  not  thicker  than  those  in 
the  trees  of  existing  forests;  but  if  vegetation  grew  previous  to 
the  flood  at  a  rate  which  the  hypothesis  requires,  we  ought  to 
find  some  evidence  of  it  in  their  structure ;  for  if  all  the  plants 
in  the  earth's  crust  grew  and  were  inhumed  between  Adam  and 
the  close  of  the  deluge,  the  antediluvian  vegetation  must  have 
grown,  according  to  the  preceding  estimates  (page  322),  7.602 
times  as  rapidly  as  the  plants  of  our  own  era. 

2.  The  same  must  have  been  true  of  animals ;  but  we  have  the 
most  convincing  evidence  in  the  structure  of  animal  relics  that 
their  growth  was  not  increased  at  a  rate  required  by  this  hy- 
pothesis. 

3.  The  character  and  position  of  the  rocks  demonstrate  that 
the  laws  which  governed  their  formation  did  not  essentially  differ 
in  activity  from  their  present  rate.     But  in  case  the  rocky  beds 
were  deposited  by  the  Noachian  deluge,  we  should  be  under 
the  necessity  of  believing  that  the  agents  of  change  operated  dur- 
ing the  year  of  the  flood  52,800,000  times  as  powerfully  as  at 

What  hypothesis  has  been  suggested  to  set  aside  the  evidence  of  the  antiqui- 
ty of  the  earth  1  What  is  said  of  this  hypothesis  ?  What  reasons  agaiqst  it 
derived  from  the  plants  ?  from  the  animals  7  from  the  rocks  ? 


324  ANTIdUITY  OF  THE  EARTH. 

present;  and,  even  if  we  allow  the  whole  time  from  Ad&m  to 
Noah  (1650  years),  then  the  agents  must  have  exceeded  32,000 
times  their  present  activity.  This  would  produce  a  state  of  agi- 
tation sufficient,  we  should  suppose,  to  preclude  the  existence  of 
animals  on  the  earth's  surface. 

4,  But  suppose  that  this  is  not  a  correct  view  of  the  case,  and 
that  animals  and  plants  could  have  flourished ;  if  it  is  maintained 
that  any  considerable  portion  of  the  changes  which  the  rocks  in- 
dicate took  place  before  the  flood,  as  the  growth  of  animals  and 
plants,  then  the  antediluvians  must  at  least  have  had  rather  tur- 
bulent times,  and,  as  frogs  grew  as  large  as  elephants,  men  would 
doubtless  have  attained  to  a  colossal  magnitude,  "  giants  indeed 
in  those  days."  We  would  suggest,  however,  to  the  believer  in 
the  hypothesis,  why  some  of  those  giants'  bones  have  not  been 
found  buried  with  his  cotemporaries  in  the  rocks  ? 

There  are  about  30,000  fossil  species  found  in  the  rocks,  and 
only  a  few,  in  the  upper  beds,  identical  with  those  that  exist  at 
the  present  day.  What  has  become  of  the  remains  of  man  and 
the  animals  which  now  inhabit  the  earth  ]  Was  there  a  new 
creation  after  the  flood  1  If  man  existed  during  the  deposition 
of  the  tertiary  and  secondary  rocks,  we  might  reasonably  expect 
to  find  some  evidence  of  it ;  some  cities  or  implements  of  hus- 
bandry would  have  been  preserved.  It  is  reasonable  to  conclude 
that  the  human  skeleton  would  be  as  durable  as  the  bones  of 
other  animals,  or  the  delicate  leaves  of  plants ;  but  no  such  re- 
mains have  been  found  below  the  alluvial  deposits.  This  fact  ap- 
pears to  settle  the  question  ;  for  if  the  waters  of  the  Noachian 
deluge  had  been  continued  sufficiently  long  to  have  deposited 
the  stratified  rocks,  the  simple  fact  that  the  bones  of  man  are  not 
associated  with  the  fossil  races  is  of  itself  a  perfect  confutation  of 
the  hypothesis  under  consideration.  For  a  fuller  discussion  of 
this  subject  the  student  is  referred  to  Hitchcock's  Religion  of 
Geology,  which  is  the  most  able  work  on  the  connection  of  sci- 
ence and  revelation  which  has  hitherto  appeared. 

What  reasons  against  this  hypothesis  derived  from  the  absence  of  the  bone* 
of  man? 


ANTiaUITY    OF    THE    EARTH.  32t» 

II.  In  order  to  account  for  the  present  nppearances  in  the 
earth's  crust,  it  has  been  suggested  that  the  laws  of  nature  were 
altered  after  the  fall  of  our  First  Parents.     This  hypothesis  does 
not  differ  essentially  from  the  preceding,  so  far  as  it  depends  upon 
natural  laws,  but  simply  assigns  a  reason  for  the  supposed  alter- 
ation.    But  we  find  no  evidence  either  in  the  Bible  or  in  the 
rocks  of  such  a  change.    The  character  of  the  fossils  proves  that 
no  such  change  has  taken  place  since  the  commencement  of  or 
ganized  life. 

III.  The  last  hypothesis  which  we  will  notice  supposes  that 
the  rocks,  with  all  their  imbedded  fossils,  were  created  exactly 
as  we  find  them  by  the  direct  power  of  God. 

A  naturalist  who  is  ignorant  of  geological  doctrines  commences 
an  examination  of  the  rocks,  and  is  surprised  to  find  the  remains 
of  several  thousand  species  of  animals  and  plants  different  from 
those  which  exist  upon  the  earth's  surface.  He  finds  them  im- 
bedded in  rocks  to  the  depth  of  several  miles,  and  preserved  in 
such  perfection  that  he  is  able  to  assign  them  their  position  in  the 
grand  scale  of  organization.  He  inquires  of  a  believer  in  the 
above  hypothesis  how  these  relics  became  buried  so  deeply  in 
the  solid  rocks.  The  answer  is,  "They  were  created  there;" 
"  the  earth  was  so  made ;"  for  he  is  told,  "  It  is  evident  that  when 
God  made  trees  he  would  make  them  with  the  concentric  rings 
of  annual  growth,  so  that  they  might  appear  to  be  several  hund- 
red years  old  on  the  day  of  their  creation.  The  same  principle 
applies  to  the  making  of  worlds."  "  He  made  the  earth  as  it 
would  have  appeared  if  it  had  existed  millions  of  years."  "  The 
fossils  and  rocky  strata  are  but  types  of  what  is  now  in  progress." 
"Would  such  an  explanation  satisfy  any  reasonable  mind  1 

We  would  not  doubt  the  power  of  God  to  form  the  earth  in 
accordance  with  the  above  hypothesis ;  but  what  he  has  done  and 
what  he  has  power  to  do  are  quite  different  propositions. 

If  the  Deity  formed  in  the  rocks  types  of  the  animals  which 
were  afterward  to  inhabit  the  earth,  why  did  he  not  give  us  a 

What  is  the  second  hypothesis,  and  what  objections  to  it  are  mentioned  ? 
the  last  hypothesis  ?  How  is  this  hypothesis  answered  T 


326  ANTIQUITY  OF  THE  EARTH. 

type  of  man  1  There  are  types  of  elephants,  bears,  whales,  birds, 
monkeys,  shell-fishes,  and  even  insects  and  worms;  why  not  a 
type  of  the  human  species?  It  is  at  least  impossible  to  conceive 
of  the  reason  unless  the  inventor  of  the  hypothesis  considers  the 
monkey  tribe  as  the  proper  type ;  and  if  so,  it  would  seem  that, 
with  regard  to  some  of  the  race,  the  type  has  not  been  greatly 
improved  upon  ;  for  we  can  not  conceive  how  any  rational  mind 
can  give  its  assent  to  an  hypothesis  so  purely  fanciful  as  this. 
And  yet,  as  it  is  the  most  plausible  of  any,  we  will  proceed  se- 
riously to  develop  its  logical  and  philosophical  bearings. 

As  the  hypothesis  sets  aside  all  secondary  agents  and  laws,  we 
have  nothing  to  guide  us  in  the  present  order  of  nature.  In  at- 
tempting to  refute  it,  therefore,  we  can  only  appeal  to  analogies, 
and  inquire  whether  such  a  view  is  consistent  with  what  we 
know  of  the  ways  of  the  Divine  Being  1  whether,  in  entertaining 
the  hypothesis,  we  must  not  adopt  principles  which  will  subvert 
all  reasoning  on  subjects  which  are  not  the  immediate  objects  of 
personal  observation1? 

The  hypothesis  is  based  on  the  assumption  that  the  uniform 
course  of  nature  must  be  set  aside  so  far  as  to  allow  of  a  begin- 
ning— a  time  when  natural  laws  were  established — so  that  with 
regard  to  the  original  production  of  man  and  other  animals,  the 
analogy  of  present  laws  is  of  no  logical  force.  This  doctrine  we 
fully  admit,  for  we  have  positive  proof  that  organic  beings  were 
first  created  by  the  direct  power  of  God.  But  all  the  processes 
and  laws  of  nature  are  not  primary  institutions,  but  many  of 
them  result  from  those  that  are.  It  is  an  axiom  in  reasoning  that 
each  law  must  be  regarded  as  having  been  the  same  in  all  past 
time,  unless  there  are  good  reasons  for  the  contrary  belief.  Thus, 
for  example,  it  is  a  uniform  law  that  animals  and  plants  are  pre- 
ceded by  similar  animals  and  plants.  How  do  we  know  that 
this  has  not  always  been  the  case  ?  We  know  that  it  has  not, 
first,  from  the  evidences  of  design  and  of  a  designer,  which  are 

What  does  this  hypothesis  set  aside  ?  upon  what  is  it  based  ?  What  is  the 
present  law  in  respect  to  the  origin  of  animals  ?  Has  this  law  ever  been  dif- 
ferent ?  What  reason  for  it  ? 


ANTIQUITY    OF    THE    EARTH.  32"* 

not  accounted  for  by  tracing  the  series  backward  even  to  infinity 
and,  secondly,  from  a  revelation  which  particularly  describes  the 
creation  of  man  and  the  present  races  of  animals  and  plants.  By 
the  first  reason  we  settle  it  as  a  fact  that  this  uniform  law  of  par- 
entage must  have  commenced  in  some  period  of  the  past,  and 
by  the  second  reason  the  time  for  the  present  races  is  assigned. 
We  can  not,  therefore,  affirm  that  every  animal  was  preceded  by 
one  of  its  kind ;  there  is  one  case,  at  least,  in  which  the  present 
order  can  not  be  made  the  basis  of  reasoning. 

Are  there  the  same  or  similar  reasons  for  setting  aside  the 
present  order  of  nature  in  our  reasonings  upon  the  formation  of 
the  rocks,  and  of  the  remains  of  animals  and  plants  which  they 
contain  ]  It  is  now  a  uniform  law  that  the  bones  of  men  and 
other  animals  belong  to  living  beings  before  they  are  entombed 
in  the  earth.  Is  there  any  reason  to  believe  that  this  law  has 
ever  been  different  1  It  is  obvious  that  there  is  no  necessity  in 
the  case,  for  the  creation  of  living  animals  and  plants  will  per- 
fectly account  for  their  existence  in  the  rocks,  and  we  have  no 
historical  record  or  revelation  of  any  kind  that  in  any  way  im 
plies  that  such  relics  were  created  as  we  find  them. 

The  admitted  fact,  then,  that  the  ordinary  course  of  nature  in 
the  production  of  organic  beings  must  be  set  aside  both  by  the 
necessity  of  a  first  creation  and  by  revelation,  can  not  be  urged 
either  logically  or  philosophically  to  dispense  with  the  law  in  re- 
spect to  the  fossil  races,  because  the  creation  of  living  beings  fully 
accounts  for  the  existence  of  their  remains  in  the  rocks. 

On  the  other  hand,  we  may  urge  the  analogy  of  the  present 
system  of  nature  to  prove  that  the  fossil  species  were  first  created 
as  living  beings. 

The  true  state  of  the  argument  is  this  :  In  the  rocks  which  aie 
now  forming  we  find  the  remains  of  man  and  other  relics  of  or- 
ganization. We  know  that  they  once  formed  parts  of  living  be- 
ings. We  next  inquire  when  the  latter  were  first  introduced, 

Are  there  similar  reasons  for  setting  aside  the  law  of  the  fossil  bodies  ?  Why 
not?  What  analogy  may  be  urged  to  prove  that  the  fossils  once  be'onged  to 
living  beings? 


328  ANTiaUITY  OF  THE  EARTH. 

and  find  a  revelation  which  fixes  the  time  to  be  about  6000  years 
since.  Beneath  these  relics,  deeper  in  the  rocks,  are  found  the 
remains  of  a  different  series  of  animals  and  plants,  such  as  have 
no  living  representatives,  and  we  infer  that  these  also  were  once 
in  a  living  state,  although  we  have  no  account  of  their  creation  ; 
but  we  infer  it  from  the  necessity  of  the  case,  and  from  the  fact 
that  revelation  has  given  us  an  account  of  the  creation  of  one  race 
which  we  know  exist  as  living  beings  before  they  are  buried  in 
the  earth. 

The  analogy,  then,  of  the  creation  before  the  inhumation  of  ex- 
isting races  may  be  urged  in  proof  of  the  creation  and  subsequent 
deposition  in  the  rocks  of  all  preceding  races ;  in  other  words, 
it  is  logically  inferred  from  the  present  law  of  the  creation  of  an- 
imals and  plants  before  their  inhumation  in  the  rocks,  that  the 
fossil  races  not  derived  from  existing  species  were  created  as 
living  creatures  before  they  were  buried  in  the  earth's  crust; 
hence  they  were  not  created  as  we  find  them. 

We  have  presented  this  argument  in  different  forms,  because 
it  has  been  so  frequently  and  boastfully  said  that  "  the  reasonings 
of  geologists  are  destitute  of  sound  logic."  "  The  earth  may 
have  been  created  so,  and  therefore  no  man  can  prove  that  it  was 
not."  "  The  most  that  can  be  said  is  that  the  antiquity  of  the 
earth  is  somewhat  probable  !" 

We  will  not  attempt  to  confute  this  hypothesis  further  by  di- 
rect argument,  but  will  allow  the  believers  in  it  the  full  benefit 
of  their  logic. 

The  mode  of  reasoning  which  the  hypothesis  adopts  would  en 
able  us  to  arrest  all  inquiries  and  settle  all  difficulties  in  respect 
to  the  whole  history  of  the  past  with  the  same  facility  with  which 
it  enables  us  to  solve  geological  problems.  The  Pyramids  and 
mummies  of  Egypt,  the  ruins  of  Pompeii  arid  of  Rome  the  cities 
of  Central  America,  can  not  be  proved  to  have  been  the  works 
of  man,  or  to  have  been  built  at  all,  because  "  they  might  have 
been  created  so."  They  are  merely  types  of  what  is  now  in 

What  would  be  the  result  of  adopting  the  mode  of  reasoning  whicfr  the  hy- 
pothesis requires  ? 


ANTiaUlTY    OF    THE    EARTH.  329* 

progress.  But  suppose  we  have  histories  of  their  origin  and  de- 
cay, ought  we  not  also  to  have  types  of  histories  ?  It  is  vast- 
ly more  reasonable  to  believe  that  all  things  whose  origin  we 
did  not  see — cities,  works  of  art,  and  men — were  created  just  as 
they  now  appear,  than  to  believe  that  the  remains  of  animals  and 
plants  were  created  deep  in  the  crust  of  the  earth;  for  we  can 
see  some  object  in  giving  existence  to  living  beings,  but  what 
possible  reason  can  be  assigned  for  the  creation  of  comminuted 
shells,  bones  of  land  quadrupeds,  saurians,  lizards,  and  croco- 
diles, in  a  more  or  less  petrified  condition ;  some  of  the  bones 
appearing  as  if  they  had  been  fractured  and  then  grown  together 
during  the  life  of  the  animal  ?  It  is  infinitely  more  reasonable  to 
believe  that  all  we  behold  is  no  evidence  of  creative  power,  than 
to  believe  that  such  power  has  been  exerted  in  the  manner  re- 
quired by  the  hypothesis. 

In  the  language  of  a  distinguished  cultivator  of  science,  Pro- 
fessor Silliman,  "  The  man  who  can  believe  that  the  iguanodon, 
with  his  gigantic  form  of  [30]  feet  in  length,  [5]  in  breadth,  and 
15  in  girth,  was  created  in  the  midst  of  consolidated  sandstones, 
and  placed  down  one  thousand  or  twelve  hundred  feet  from  the 
surface  of  the  earth,  in  a  rock  composed  of  ruins  and  fragments, 
and  containing  vegetables,  shell-fish,  and  rounded  pebbles,  such 
a  man  can  believe  any  thing,  either  with  or  without  evidence. 
He  must  be  left  to  his  own  reflections,  since  he  can  not  be  reach- 
ed by  sound  argument;  with  such  men  discussion  is  useless,  for 
the  foundation  of  all  conviction  or  persuasion  is  removed." 

Let  us  then  banish  such  fancies  from  the  works  of  God,  and 
with  our  Bibles  in  our  hands  meet  this  question  of  the  antiquity 
of  the  earth,  and  show,  by  comparing  record  with  record,  that 
both  may  be  received,  because  both  proceed  from  the  same  great 
fountain  of  light  and  truth. 


330  GEOLOGY    AND    NATURAL   THEOLOGT. 


CHAPTER  XI. 

CONNECTION  OF  GEOLOGY  WITH  NATURAL  THEOLOGY  AND 
WITH  REVELATION. 

HAVING  presented  the  physical  evidence  of  the  antiquity  of  the 
earth,  there  are  two  other  subjects  which  are  so  intimately  con- 
nected with  the  doctrines  of  geology,  that  a  brief  discussion  of 
them  seems  necessary  to  the  completeness  of  the  present  work. 
These  subjects  are  the  evidences  furnished  by  geology  for  the 
existence  and  attributes  of  God,  and  the  apparent  discrepancies 
between  the  records  of  geology  and  the  Mosaic  history. 

SECTION  I.-GEOLOGY  AND  NATURAL  THEOLOGY. 

The  evidence  furnished  by  geology  in  proof  of  the  existence 
and  attributes  of  God,  is  the  same  in  kind  with  that  furnished 
by  the  earth  and  its  inhabitants  at  the  present  time.  The  same 
evidences  of  design,  and  therefore  of  a  designer,  meet  us  in  every 
period  of  geological  history. 

But  most  of  the  arguments  derived  from  the  existing  condition 
of  the  earth  are  greatly  extended,  and  their  truth  more  variously 
and  fully  confirmed. 

I.  The  changes  to  which  the  earth  has  been  subjected  require 
the  exertion  of  infinite  Power. 

This  is  seen  in  the  frequent  changes  of  sea  and  land,  the  long- 
continued  action  of  aqueous  and  igneous  forces  by  which  the 
earth  has  been  molded  into  its  present  form,  but  more  especially 
in  the  creation  and  distribution  of  many  distinct  races  of  organic 
beings.  We  can  trace  the  remains  of  organization  in  the  rocks 
of  the  earth's  surface,  until  we  reach  a  period  of  its  history  when 
the  condition  of  its  mineral  masses  precluded  the  existence  of 

What  two  subjects  are  discussed  in  this  chapter  ?  What  is  the  nature  of  the 
evidence  furnished  by  geology  in  proof  of  the  existence  and  attributes  of  God  ? 
What  evidsnces  that  organic  beings  had  a  beginning? 


GEOLOGY    AND    NATURAL    THEOLOGY.  331 

life.  This  fact  entirely  sets  aside  the  hypothesis  of  "an  eternal 
succession  of  animals  and  plants."  They  had  a  beginning,  and 
this  required  creative  power. 

This  power  has  been  exerted  at  successive  periods,  as  is  shown 
by  the  new  families  which  have  from  time  to  time  been  intro- 
duced ;  and  hence  the  records  of  geology  furnish  numerous  ad- 
ditional examples  of  the  exertion  of  creative  power,  which  greatly 
enlarge  our  ideas  of  the  extent  of  this  attribute  of  the  Divine 
Being. 

II.  The  structure  and  adaptation  of  the  successive  races  of  or- 
ganic beings  which  have  peopled  the  earth  during  its  past  his- 
tory to  the  conditions  of  its  surface  show  that  power  was  guided 
by  intelligence  and  wisdom. 

The  evidence  of  this  appears  in  the  anatomical  structure  and 
habits  of  the  particular  types  of  organization  which  prevailed 
during  each  of  the  geological  periods.  Every  change  in  the 
mineral  masses,  in  the  climate  and  surface  of  the  earth,  was  at- 
tended by  corresponding  changes  in  the  animal  and  vegetable 
races.  Previous  to  the  coal  period,  the  atmosphere  was  so 
charged  with  carbonic  acid  as  to  preclude  the  existence  of  air- 
breathing  animals,  and  to  favor  a  luxuriant  tropical  vegetation. 
Immediately  after  the  coal-beds  were  deposited,  the  atmosphere 
became  deprived  of  a  large  portion  of  its  carbon,  and  birds  are 
for  the  first  time  introduced.  During  the  succeeding  periods, 
down  to  the  tertiary,  the  condition  of  the  earth  was  fitted  to  rep- 
tiles, and  they  were  the  prevailing  forms  of  life.  At  the  com- 
mencement of  the  tertiary  the  surface  had  become  suited  to  land 
quadrupeds,  and  they  are  then  introduced. 

III.  In  all  the  varieties  of  form  and  structure  in  the  organic 
and  inorganic  kingdoms  of  nature  there  is  perfect  unity  of  design. 
From  the   earliest  geological  times  to  the  present  period  the 
same  physical  and  vital  laws  have  prevailed.     The  rocks  of  every 
period  show,  by  their  composition,  structure,  and  physical  prop- 
erties, that  they  were  under  the  influence  of  the  same  atomic, 

"What  proof  is  this  of  power  ?     What  evidence  does  geology  furnish  of  iutel- 
igence  and  wisdom  1     What  of  the  unity  of  God  ? 


332  GEOLOGY   AND    NATURAL    THEOLOGY. 

chemical,  and  electrical  attractions,  the  same  gravitating  forces 
as  at  present. 

The  four  great  divisions  of  the  animal,  and  the  prevailing  types 
of  the  vegetable  kingdoms,  were  established  at  the  commence- 
ment of  organic  life,  and  amid  great  variety  of  form  and  struc- 
ture, in  successive  periods,  the  general  plan  is  always  preserved. 
The  laws  Df  anatomy  and  physiology  are  ever  the  same.  Each 
group  of  rocks,  and  each  family  of  animals  and  plants,  have  an 
intimate  and  fixed  relation.  One  uniform  plan,  the  same  great 
thought  of  the  divine  mind,  pervades  the  whole.  Each  served  its 
appropriate  end,  and  contributed  to  the  final  result  of  preparing 
the  earth  to  become  the  fit  habitation  of  intellectual  and  moral 
beings. 

The  unity  of  the  divine  intelligence,  as  evinced  in  the  character 
of  the  fossil  races,  is  most  forcibly  presented  by  Dr.  Buckland  in 
his  Bridge  water  Treatise.  "  There  is,"  says  he,  "  such  a  never- 
failing  identity  in  the  fundamental  principles  of  their  construc- 
tion, and  such  uniform  adoption  of  analogous  means  to  produce 
various  ends,  with  so  much  only  of  departure  from  one  common 
type  of  mechanism  as  was  requisite  to  adapt  each  instrument  to 
its  own  especial  function,  and  to  fit  each  species  to  its  peculiar 
place  and  office  in  the  scale  of  created  beings,  that  we  can  scarce- 
ly fail  to  acknowledge  in  all  these  facts  a  demonstration  of  the 
unity  of  the  intelligence  in  which  such  transcendent  harmony 
originated ;  and  we  may  almost  dare  to  assert  that  neither  athe- 
ism nor  polytheism  would  ever  have  found  acceptance  in  the 
world  had  the  evidences  of  high  intelligence  and  unity  of  design 
which  have  been  disclosed  by  modern  discoveries  in  physical 
science  been  fully  known  to  the  authors  or  abettors  of  systems  to 
which  they  are  so  diametrically  opposed.  It  is  the  same  hand- 
writing that  we  read,  the  same  system  and  contrivance  that  we 
trace,  the  same  unity  of  object  and  relation  to  final  causes  which 
we  see  maintained  throughout,  and  constantly  proclaiming  the 
unity  of  the  great  divine  original." 

IV.  In  all  periods  of  the  earth's  history,  the  power,  wisdom,  and 
unity  of  the  Divine  Being  have  always  been  attended  with  be- 


GEOLOGY  AND  NATURAL  THEOLOGY.          333 

nevoZence,  that  is,  with  the  design  of  imparting  happiness  to  living 
creatures,  and  to  make  provision  for  higher  developments  of  the 
divine  goodness  in  the  future  beings  which  were  to  be  introduced. 

The  changes  which  preceded  the  first  animals  had  direct  ref- 
erence to  their  enjoyment.  They  were  adapted  in  form  and 
habits  to  the  condition  of  the  mineral  masses.  The  successive 
sedimentary  deposits,  and  the  convulsions  which  have  thrown 
the  surface  into  ridges,  mingling  those  ingredients  which  were 
necessary  to  support  vegetable  life,  contributed  each  to  increase 
the  aggregate  of  animal  enjoyment.  The  introduction  of  car- 
nivorous races  even  had  the  same  tendency,  by  restraining  a  too 
excessive  multiplication  of  any  particular  species,  and  by  pre- 
venting the  miseries  connected  with  the  infirmities  of  age  and 
of  a  natural  death. 

But  we  see  more  particularly  the  Divine  benevolence  in  those 
provisions  which  were  made  for  the  benefit  of  man  ag<3s  before 
his  appearance  on  earth. 

These  are  seen  in  the  prolific  vegetation  of  the  carboniferous 
period  during  which  the  materials  for  fossil  coal  were  preparing, 
were  stored  up  in  the  rocks,  and,  through  the  long  ages  that  suc- 
ceeded, were  gradually  wrought  into  their  present  condition,  so 
that  when  the  earth  should  be  disrobed  of  its  forests,  man  should 
have  his  wants  supplied  from  these  ancient  stores  of  vegetation, 
and  be  reminded  constantly  of  the  prospective  benevolence  of 
the  Creator. 

The  mines  of  valuable  ores  and  minerals,  in  their  distribution 
and  abundance,  are  examples  of  the  same  benevolent  provision. 

The  whole  series  of  volcanic  and  aqueous  agencies  by  which 
the  primitive  materials  have  been  molded  into  their  present 
forms,  giving  rise  to  that  almost  infinite  variety  of  scenery  which 
the  surface  of  the  earth  presents,  and  of  productions  to  which  it 
has  thus  been  fitted,  evince  foresight  and  benevolence  in  the 
Creator  which  challenges  our  profound  gratitude  and  love.  It  is 
true  that  the  past  as  well  as  the  present  condition  of  the  earth 

Mention  the  several  facts  which  prove  the  benevolence  of  the  Deity! 
What  instances  oi  prospective  benevolence  ? 


334  GEOLOGY    AND    NATURAL    THEOLOGY. 

has  been  such  that  the  Divine  benevolence  has  been  obscured ; 
good  and  evil  have  been  mingled  in  the  development  of  the  Di- 
vine plan,  but  benevolence  prevails  in  all,  and  if  we  were  able  to 
look  through  the  whole  system,  pain  and  apparent  evil  would  no 
doubt  be  seen  to  result  directly  from  infinite  goodness. 

In  addition  to  what  was  absolutely  necessary  to  maintain  the 
existence  of  man  and  other  animals,  there  is  much  that  is  in- 
tended to  gratify  his  taste  and  regale  his  senses.  The  scenery 
of  the  earth,  its  varied  surface  of  mountains  and  valleys,  its  rivers 
and  oceans,  its  ever-changing  views,  its  gorgeous  colorings,  these 
are  ever  filling  the  soul  with  grateful  emotions.  The  thousand 
voices  of  the  earth,  its  wonderful  harmonies,  its  silences  even,  all 
tend  to  increase  the  happiness  of  sentient  beings.  This  condi- 
tion of  the  earth  has  been  slowly  maturing  during  the  long  ages 
of  the  past,  and  most  beautifully  arid  strikingly  illustrates  the 
prospective  benevolence  of  the  Creator.  The  records  of  geol- 
ogy, when  fairly  interpreted,  all  unite  in  proving  and  illustrating 
the  attributes  of  God  ;  they  show  that  he  is  a  God  of  power,  wis- 
dom, and  benevolence,  and  that,  amid  all  the  changes  of  material 
forms,  he  is  unchangeably  the  same. 

V.  But  the  greatest  aid  which  geology  has  rendered  to  natural 
theology  is  in  enlarging  our  ideas  of  the  system  of  the  world  and 
of  the  plans  of  God. 

Until  the  time  of  Copernicus,  the  space  in  which  the  universe 
was  supposed  to  be  contained  was  very  limited,  confined  within 
a  crystalline  hollow  globe  of  inconsiderable  diameter  called  the 
firmament;  but  so  soon  as  the  telescope  was  directed  to  the 
heavens,  this  firmament  was  found  to  have  no  existence,  and  the 
idea  of  boundless  space,  filled  with  the  display  of  God's  power 
dawned  upon  the  minds  of  men. 

In  the  same  way  geology  has  enlarged  our  ideas  of  the  time 
during  which  the  universe  has  existed.  Until  within  a  very  re- 
cent period,  the  idea  was  almost  universal  that  the  heavens  and 

Does  not  pain  and  evil  in  the  world  militate  against  the  benevolence  of 
God  ?  Why  not  ?  What  other  illustration  of  benevolence  ?  In  what  has  g» 
ology  rendered  the  greatest  aid  to  natural  theology  ? 


CONNECTION  OP  GEOLOGY  WITH  REVELATION.     335 

the  earth  were  created  about  six  thousand  years  since ;  but  an  ex- 
amination  of  the  rocks  brings  to  view  a  series  of  changes,  which 
stretch  backward  through  periods  of  such  amazing  length,  that 
the  imagination  is  not  able  to  fix  the  time  of  the  beginning,  and 
from  the  analogies  which  come  up  from  the  past,  we  are  point 
ed  forward  to  indefinite  ages  during  which  man  and  his  cotem- 
porary  races  will  work  out  the  grand  purposes  of  their  earthly 
existence ;  and  not  only  so,  but  from  the  changes  to  which  the 
earth  has  been  subjected,  we  may  believe  that  other  changes  will 
take  place  which  will  sweep  away  the  present  races  of  animals 
and  plants,  and  that  new  and  higher  forms  of  organic  beings  will 
inhabit  the  renovated  earth. 

It  is  thus  that  the  records  of  geology  carry  us  backward  fai 
beyond  the  time  when  human  history  began,  and  point  us  to  in- 
definite ages  after  it  shall  have  been  completed.  How  does  it 
exalt  and  enlarge  our  ideas  of  the  plans  of  God !  How  great 
is  his  power,  how  unsearchable  his  wisdom,  how  wonderful  his 
benevolence  !  Surely  "  His  understanding  is  infinite  !" 

SECTION  II.— CONNECTION  OF  GEOLOGY  WITH  REVELATION. 

The  material  universe  gives  abundant  proof  and  illustration  of 
the  being  and  attributes  of  God.  Its  purpose  appears  to  have 
been  to  exhibit  the  divine  character  to  finite  intelligences. 

First,  we  have  presented  the  attribute  of  power  in  the  crea 
tion  of  matter.  Secondly,  we  find  in  addition  to  power,  wisdom 
and  intelligence  in  its  arrangement.  Thirdly,  to  these  are  added 
benevolence  and  providential  care  in  its  properties,  uses,  and  gov- 
ernment. And  as  each  successive  development  was  more  and 
more  glorious,  as  was  shown  particularly  in  the  higher  orders  of 
beings  which  were  formed,  we  should  expect,  after  the  creation 
of  man  the  most  exalted  of  all,  an  exhibition  of  other  attributes 
which  pertain  to  his  nature  as  spiritual  and  immortal.  The  cre- 
ation of  an  intellectual  and  moral  race  would  lead  to  the  expec- 
tation that  God  would  make  a  revelation  suited  to  their  wants. 

From  the  history  of  the  past  what  change  may  be  expected  ?  After  the  cre- 
ation of  man,  what  kind  of  a  revelation  was  to  be  expected  ? 


J336  CONNECTION    OP    GEOLOGY    WITH    REVELATION. 

Such  a  revelation  has  been  given  in  the  Bible.  This  manifest- 
ation of  his  higher  attributes — his  moral  character-  -harmonizes 
with  all  his  other  revelations.  In  fact,  each  record  confirms  the 
truth  of  the  other,  and  proves  both  to  be  from  the  same  divine 
intelligence  and  wisdom.  From  the  infinite  nature  of  God,  how- 
ever— from  the  imperfection  of  language,  and  the  difficulty  of 
rightly  interpreting  these  records,  we  might  anticipate  apparent 
discrepancies ;  an  expectation  which  has  been  abundantly  con- 
firmed in  the  history  of  the  past.  At  $ie  present  time,  the  most 
important  differences  refer  to  the  age  of  the  world,  and  the  in- 
troduction of  death.  We  shall  therefore  conclude  the  present 
work  by  a  very  brief  discussion  of  these  topics. 

I.  There  is  an  apparent  discrepancy  between  the  Mosaic  and  ge 
ological  records  in  respect  to  the  age  of  the  world. 

We  have  presented  the  reasons  for  believing  that  the  earth  has 
existed  for  a  much  longer  period  than  six  thousand  years,  and 
the  question  is,  whether  the  language  of  the  first  chapter  of  Gen- 
esis definitely  fixes  the  time  of  the  creation  of  the  universe.  "In 
the  beginning  God  created  the  heavens  and  the  earth,"  is  the 
majestic  and  sublime  language  with  which  the  sacred  record  com- 
mences. It  should  be  noticed, 

1.  That  the  phrase  "  in  the  beginning"  does  not  refer  to  time 
absolutely,  but  to  the  commencement  of  any  period,  process,  or 
series  of  events,  and  is  always  limited  by  the  subject  to  which  it 
is  attached,  as  the  beginning  of  a  kingdom,  of  the  reign  of  a  king, 
the  beginning  of  life,  &c.  It  undoubtedly,  therefore,  in  this  case, 
refers  to  the  time  when  the  universe  was  created.  The  revela- 
tion commences  by  ascribing  the  origin  of  all  things  to  the  power 
of  God,  in  opposition,  no  doubt,  to  the  views  of  heathen  nations, 
which  referred  the  creation  of  the  universe  to  inferior  deities,  to 
chance,  or  to  the  belief  that  it  was  eternal.  The  heavens  and 
the  earth  were  absolutely  created  by  the  God  of  the  Hebrews. 
There  can  be  no  doubt,  therefore,  but  that  the  first  verse  refers 

Has  such  a  revelation  been  given?  What  apparent  discrepancies  are  no- 
ticed ?  What  does  the  phrase  "  in  the  beginning"  mean  ?  Does  it  fix  the  ex 
act  time  of  the  creation? 


CONNECTION  OF  GEOLOGY  WITH  REVELATION.     33? 

10  the  time  when  the  material  universe  was  first  brought  into 
being. 

2.  The  simple  inquiry  now  is,  whether  this  first  verse  is  a  gen- 
eral caption  to  the  remainder  of  the  chapter,  or  whether  it  is  an 
independent  proposition  not  connected  with  what  follows,  but 
intended  merely  to  ascribe  the  origin  of  all  things  to  God.  That 
is,  whether  the  time  of  the  beginning  was  about  six  thousand 
years  since,  or  whether  it  is  left  undetermined.  It  is  obvious  that 
either  interpretation  may  be  adopted,  so  far  as  the  language  itself 
is  concerned.  It  has  been  quite  generally  considered  as  a  gen- 
eral assertion,  the  particulars  of  which  are  stated  in  subsequent 
verses,  although  many  commentators  have  regarded  it  as  an  in- 
dependent statement,  irrespective  of  the  facts  of  geology. 

By  what  means  now  can  the  true  interpretation  be  settled  1 
The  Bible  is  to  be  interpreted  like  any  other  ancient  record,  that 
is,  by  considering  the  object  of  the  record,  the  character,  knowl- 
edge, and  condition  of  the  writers,  and  of  those  to  whom  the  writ- 
ing was  addressed.  By  considering  these  points  and  others,  we 
may  be  guided  to  a  true  interpretation,  and  to  a  solution  of  the 
difficulties  which  the  believers  in  revelation  have  often  found  in 
the  records  of  science. 

(1.)  The  object  of  a  revelation  was  to  instruct  men  in  respect  to 
their  duty  and  destiny  as  moral  beings,  and  not  to  teach  them 
physical  science.  The  reason  of  this  is  very  obvious.  God  had 
given  the  evidences  of  his  existence  and  his  natural  attributes  in 
the  material  universe.  He  had  endowed  man  with  powers  capa- 
ble of  investigating  and  of  reading  this  revelation  ;  these  were 
sufficient  for  him  as  a  physical  being ;  but  he  needed  more ;  he 
needed  instruction  in  respect  to  his  spiritual  and  immortal  na- 
ture, and  this  he  could  not  find  in  the  works  of  God.  To  supply 
this  knowledge,  a  revelation  direct  from  God  must  be  given,  and 
such  is  the  object  of  the  Bible,  as  appears  in  every  page  from  the 
beginning  to  the  end.  Had  the  Bible  undertaken  to  teach  sci- 
ence, we  could  not  have  received  it  as  a  revelation  from  God,  in- 

What  is  the  next  inquiry  f  How  is  the  Bible  to  be  interpreted  ?  Whit  was 
the  object  of  a  revelation  ? 

P 


338     CONNECTION  OF  GEOLOGY  WITH  REVELATION. 

asmuch  as  a  revelation,  in  order  to  be  credible,  must  make  known 
that  which  our  natural  powers  are  otherwise  incapable  of  discov- 
ering. 

(2.)  The  people  to  whom  the  revelation  was  first  given  were 
just  emerging  from  a  state  of  slavery,  of  semi-barbarism,  and 
were  wholly  ignorant  of  the  principles  of  science,  for  the  sciences 
did  not  then  exist.  They  had  no  idea  of  secondary  forces,  but 
ascribed  every  change  to  the  direct  power  of  God.  The  heav- 
enly bodies  were  moved  by  his  hand  ;  they  heard  his  voice  in 
the  thunder;  he  opened  the  windows  of  heaven  in  the  solid  firm- 
ament but  just  above  their  heads,  and  poured  out  rain  to  water 
the  earth;  consequently,  all  natural  phenomena  were  regarded 
according  to  apparent  rather  than  actual  truth.  As  revelation 
was  not  intended  to  controvert  these  views,  but  to  communicate 
spiritual  truth,  its  language  must  be  adapted  to  the  necessities  of 
the  case.  The  people  could  not,  without  miraculous  agency, 
have  understood  it,  if,  when  it  referred  to  the  material  universe, 
it  had  adopted  language  which  should  be  scientifically  accurate  ; 
and  hence,  in  condescension  to  the  views  of  men  in  a  rude  state 
of  society,  God  wonderfully  adapted  his  revelation  in  style  and 
manner  to  their  necessities.  It  was  no  part,  therefore,  of  his  pur- 
pose to  teach  them  the  chronology  of  the  earth — neither  Moses 
nor  the  people  could  have  understood  him  if  he  had  made  the  at- 
tempt— but  to  give  the  origin  of  the  human  race,  and  its  rela- 
tions to  himself.  Considering,  then,  the  object  of  revelation,  and 
the  condition  of  men  at  the  time,  we  are  at  perfect  liberty  to  re- 
gard the  first  verse  in  Genesis  as  separate  from  the  remainder 
of  the  chapter.  The  Hebrew  particle  which  connects  the  next 
verse  with  it,  rendered  and,  is  well  known  to  be  generally  used 
simply  to  connect  the  language,  and  not  the  sense.  It  is  often 
rendered  but  and  afterward,  and  may  be  rendered  in  this  case, 
"  Afterward  the  earth  became  waste  and  desolate."  How  long 

What  was  the  character  of  the  people  to  whom  the  revelation  was  given  ? 
What  were  their  ideas  of  natural  phenomena  ?  Could  they  have  understood 
a  scientific  explanation  1  How  is  the  first  verse  of  the  first  chapter  of  Genesis 
to  be  understood  ? 


CONNECTION  OF  GEOLOGY  WITH  REVELATION.     339 

afterward  we  are  not  informed.  It  may  have  been  millions  of 
years,  during  which  all  the  changes  required  by  geology  may 
have  taken  place. 

(3.)  As  the  language  of  the  first  chapter  admits  of  two  inter- 
pretations, it  is  obvious  that  this  is  a  case  in  which  the  facts  of 
science  may  be  brought  forward  to  determine  which  shall  be 
adopted.  The  evidence  of  the  great  age  of  the  world  derived 
from  geology  and  astronomy  is  sufficient  to  decide  this  question, 
and  we  not  only  are  at  liberty,  but  are  compelled  to  believe  that 
between  the  beginning  and  the  six  days  of  creation  a  period  in- 
tervened of  which  revelation  gives  us  no  account. 

If  we  adopt  this  interpretation  of  the  first  chapter,  viz.,  that 
between  the  original  creation  of  the  universe  and  the  six  days' 
work  a  long  period  of  time  intervened,  the  difficulty  in  respect  to 
the  great  age  of  the  world  will  be  wholly  obviated. 

3.  The  only  remaining  inquiry  is,  whether  such  an  interpreta- 
tion is  consistent  with  succeeding  verses,  and  with  other  portions 
of  the  sacred  narrative "?  Keeping  in  view  the  principle  that 
the  language  of  this  chapter  is  descriptive  of  the  appearance  as 
viewed  by  a  human  spectator,  let  us  examine  the  remaining 
verses. 

"  And  the  earth  was  without  form,  and  void  ;  and  darkness  was 
upon  [brooded  over]  the  face  of  the  deep."  "  Without  form,  and 
void,"  means  laid  waste,  not  what  is  generally  understood  as  a 
chaos.  The  language  does  not  describe  a  chaos,  but  a  wasted, 
agitated  condition  of  the  earth.  It  had  experienced  a  revolu- 
tion. The  whole,  or,  more  probably,  portions  of  its  surface,  had 
been  agitated  by  volcanic  agency,  and  the  darkness  was  due  to 
vapors  and  volcanic  ashes,  which  usually  accompany  eruptions, 
and  which  often  become  so  dense  as  to  obscure  the  light  of  the 
sun  (see  page  50). 

"  And  the  spirit  of  God  (that  is,  the  wind)  moved  over  the 


Are  we  at  liberty  to  make  use  of  the  facts  of  Science  in  interpreting  the 
Bible '  How  is  the  apparent  discrepancy  of  the  two  records  reconciled  ? 
What  is  the  meaning  of  the  phrase  "without  form,  and  void?"  How  was 
this  state  produced  ?  What  does  the  phrase  "  spirit  of  God"  mean  ? 


840     CONNECTION  OF  GEOLOGY  WITH  REVELATION. 

face  of  the  waters."  This  drove  away  the  clouds  and  mists,  so 
that  the  light  shined  through  the  dark  and  murky  atmosphere. 
To  the  Hebrew  mind  whatever  appeared  was  described  as  pro- 
duced directly  by  the  command  of  God.  "  And  God  said.  Let 
there  be  light :  and  there  was  light." 

This  completes  the  first  day's  work.  On  the  second  day  the 
firmament  was  made,  that  is,  the  clouds  ascended  above  the 
earth.  The  language  is  fitted  to  the  idea  which  was  entertained 
in  the  time  of  Moses,  that  there  was  a  solid  firmament,  above 
which  rain,  hail,  and  thunder  were  stored,  and  through  which 
windows  were  made,  to  allow  them  to  descend  to  the  earth.  Thp 
same  idea  prevailed  until  within  a  recent  period. 

On  the  third  day  the  land  and  water  were  separated.  This 
was  doubtless  brought  about  by  elevations  and  depressions  of 
land,  and  appears  to  have  been  the  termination  of  the  agitations 
of  the  earth,  and  the  vegetable  kingdom  was  created.  It  is  not 
necessary  to  understand  this  description  as  having  reference  to 
aL  the  species  that  now  exist,  but  to  those  which  were  in  the  re- 
gion of  this  disturbance,  and  such  as  were  necessary  for  the  use 
of  the  animals  that  were  to  be  formed. 

On  the  fourth  day  the  sun  and  moon  were  appointed  for  signs 
and  seasons.  The  language  here,  "And  God  made  two  great 
lights,"  does  not  mean  that  they  were  then  created,  but  appoint- 
ed for  signs  and  seasons  to  the  new  order  of  beings  which  were 
to  follow.  The  atmosphere  had  now  become  so  cleared  of  vapors 
that  the  sun  and  moon  were  distinctly  visible  to  a  spectator  upon 
the  earth.  The  sun  is  the  greater  light,  and  the  moon  the  lesser. 
"  He  made  the  stars  also."  This  statement  shows  that  the  lan- 
guage was  adapted  to  human  observers,  who  were  ignorant  of 
the  extent  of  the  universe  ;  for  we  now  know  that  the  sun,  moon, 
and  earth,  the  whole  solar  system,  constitute  but  a  point  corn- 
In  what  way  was  the  light  created  ?  why  this  interpretation  ?  What  ideas 
had  the  Hebrews  of  a  firmament  ?  How  was  the  land  and  water  separated  1 
Is  it  probable  that  all  the  vegetables  now  existing  were  created  at  that  time  * 
How  is  the  language  respecting  the  creation  of  the  sun,  moon,  and  stars  to  b« 
interpreted  ? 


CONNECTION  OF  GEOLOGY  WITH  REVELATION.     341 

pared  with  "  the  stars,"  and  yet  a  single  sentence  is  all  that  is 
devoted  to  them. 

On  the  fifth  day  animals  were  created.  This  representation 
does  not  necessarily  imply  that  the  whole  animal  kingdom  was 
then  created,  foi  there  is  no  violence  done  to  the  language  of 
the  Bible  by  restricting  the  meaning  of  terms  which  describe  a 
largo  quantity  or  number.  In  these  cases  universal  terms  are 
usually  employed  :  all,  the  whole,  are  employed  to  describe  a 
large  part.  The  reader  will  find  numerous  examples  of  this  use 
of  language  in  the  Sacred  writings,  particularly  in  describing  the 
plagues  of  Egypt :  "  All  the  cattle  died,"  "  all  the  vegetation  was 
destroyed,"  &c.,  and  yet  we  find  cattle  and  vegetables  spoken  of 
immediately  afterward. 

Last  of  all,  on  the  sixth  day,  man,  the  most  exalted  creature 
of  earth,  was  created  in  the  image  of  his  Maker,  endowed  with  a 
spiritual  and  immortal  nature,  and  fitted  to  have  dominion  over 
all  the  other  works  of  God.  This  whole  scene  was  one  of 
amazing  grandeur.  It  was  no  doubt  witnessed  by  the  heavenly 
intelligences,  and,  as  the  first  formed  pair  walked  erect  in  the 
sacred  garden,  in  the  vigor  and  grace  of  their  new  life,  in  holy 
communion  with  each  other,  and  with  their  heavenly  Father,  the 
choirs  of  heaven  assembled,  the  morning  stars  sang  together,  and 
all  the  "Sons  of  God  shouted  for  joy." 

The  theory,  then,  which  obviates  the  difficulty  which  appears 
to  exist  between  the  Mosaic  and  geological  records,  is  simply  that, 
after  the  creation  of  the  universe,  the  earth  existed  for  an  un- 
known period,  during  which  the  geological  changes  which  we 
have  sketched  in  this  work  took  place,  to  describe  which  it  was 
not  the  purpose  of  a  revelation,  and  that  it  was  afterward  thrown 
into  a  desolate  state,  and  then  fitted  up  in  six  literal  days  for  the 
habitation  of  man  and  his  cotemporary  races. 

It  should  be  observed,  however,  that  several  other  theories,  to 

Is  is  necessary  to  suppose  that  all  the  species  of  animals  were  created  on 
the  fifth  day?  why  not?  What  was  the  last  act  of  creation?  What  other 
theory  has  been  proposed  to  reconcile  the  language  of  revelation  with  the 
facts  of  science  ? 


342     CONNECTION  OF  GEOLOGY  WITH  REVELATION. 

reconcile  these  two  records  have  been  proposed,  the  most  im- 
portant of  which  was  proposed  by  Jameson,  and  supposes  that 
the  six  days  of  the  creation  were  long  periods  of  time,  during 
which  geological  changes  were  in  progress  ;  £nd  many  still  adhere 
to  this  view.  But  there  are  certainly  very  afaffig  objections  to  it. 

The  Mosaic  history  represents  the  vegetable  kingdom  to  have 
been  created  on  the  third  day ;  but  an  examination  of  the  rocks 
shows  us  that  animals  were  created  as  early  as  vegetables;  they 
are  found  in  the  lowest  rocks  which  contain  any  remains  of  organ- 
ized beings.  "We  should  expect  to  find  the  remains  of  the  plants 
which  flourished  during  that  long  third  day,  but  there  is  at  least 
no  evidence  that  the  coal  vegetation  answers  to  this  description. 

Another  objection  to  this  hypothesis  is,  that  the  vegetables  and 
animals  that  now  exist  are,  with  a  few  exceptions,  specifically 
different  from  those  found  in  the  rocks,  and  different  families 
have  been  created  and  destroyed  at  several  different  and  distant 
epochs,  facts  which  can  not  be  reconciled  with  the  idea  that  the 
six  days  of  creation  were  long  periods,  for  during  nearly  every 
period  both  animals  and  vegetables  were  created,  and  peopled 
the  earth  and  the  waters. 

The  fact,  too,  stated  in  the  second  chapter,  that  no  rain  had 
taken  place  until  about  the  time  of  the  creation  of  man,  is  cer- 
tainly inconsistent  with  the  idea  that  the  days  were  long  periods, 
for  we  have  positive  proof  on  this  subject :  the  impressions  of  rain 
drops  have  been  preserved  in  many  of  the  rocks.  But  if,  during 
the  time  these  rocks  were  forming,  the  earth  was  watered  by  a 
mist,  it  is  impossible  to  account  for  their  existence.* 

In  order  to  substantiate  the  views  suggested  in  this  section,  a 
few  extracts  from  distinguished  writers  on  this  subject  are  added: 

"  A  philological  survey  of  the  initial  section  of  the  Bible  (Gen., 
i.,  1,  to  ii.,  3)  brings  out  the  result, 

"  1.  That  the  first  sentence  is  a  simple,  independent,  all-com- 

*  The  reader  should  consult  on  this  subject  President  Hitchcock's  Religion 
of  Geology,  Dr.  J.  Pye  Smith's  Lectures,  and  Dr.  Buckland's  Bridgewater 
Treatise. 

What  objection  to  this  theory  ? 


CONNECTION  OP  GEOLOGY  WITH  REVELATION.     343 

prehending  axiom  to  this  effect :  that  matter,  elementary  or  com- 
bined, aggregated  only  or  organized,  and  dependent  sentient  and 
intellectual  beings,  have  not  existed  from  eternity,  either  in  self- 
continuity  or  succession,  but  had  a  beginning  ;  that  their  begin- 
ning took  place  by  the  all-powerful  will  of  ONE  BEING,  the  Self- 
existent,  Independent,  and  Infinite  in  all  perfections ;  and  that 
the  date  of  that  beginning  is  not  made  known. 

"  2.  That,  at  a  recent  epoch,  our  planet  was  brought  into  a 
state  of  disorganization^  detritus,  or  ruin  (perhaps  we  have  no 
perfectly  appropriate  term),  from  a  former  condition. 

"  3.  That  it  pleased  the  Almighty,  Wise,  and  Benevolent  Su- 
preme, out  of  that  state  of  ruin,  to  adjust  the  surface  of  the  earth 
to  its  now  existing  condition,  partly  by  the  operation  of  the  me- 
chanical and  chemical  causes  (what  we  usually  call  Laws  of 
Nature)  which  Himself  had  established,  and  partly — that  is,  when 
ever  it  was  necessary — by  His  own  creative  power,  or  other  im- 
mediate intervention;  the  whole  extending  through  the  period 
of  six  natural  days. 

"  It  has  been,  indeed,  maintained,  that  the  conjunction  and, 
rvith  which  the  next  sentence  begins,  connects  the  succeeding 
matter  with  the  preceding,  so  as  to  forbid  the  intercalating  of 
•uiy  considerable  space  of  time.  To  this  we  reply,  that  the  He- 
brew conjunction,  agreeably  to  the  simplicity  of  ancient  lan- 
guages, expresses  an  annexation  of  subject  or  a  continuation  of 
speech,  in  any  mode  whatever,  remote  as  well  as  proximate. 
For  denoting  such  different  modes  of  annexation,  the  Greek  and 
other  languages  have  a  variety  of  particles ;  but  their  use  is,  in 
Hebrew,  compensated  by  the  shades  of  meaning  which  the  tone 
in  oral  speech,  and  the  connection  in  writing,  could  supply.  To 
go  no  further  than  the  first  two  leaves  of  the  Hebrew  Bible,  we 
find  this  copula  rendered  in  our  authorized  version  by  thus,  but, 
now,  and  also. 

"  This  interpretation  is  wrhat  I  have  been  laboring  to  diffuse 
for  more  than  thirty  years,  in  private  and  in  public,  by  preach- 
ing, by  academical  lecturing,  and  by  printing.  But  it  is  not  my 
interpretation,  though  I  believe  that  I  originally  derived  it  from 


344     CONNECTION  OF  GEOLOGY  WITH  REVELATION. 

the  sole  study  of  the  Bible-text.  Clemens  of  Alexandria,  Origen 
Basil,  Chrysostom,  and  Augustine,  among  the  fathers  (though 
not  in  a  truly  philosophical  way,  which  was  not  to  be  expected), 
departed  from  the  vulgar  notion  ;  and  some  judicious  interpret- 
ers of  the  sixteenth  and  seventeenth  centuries  have  done  the 
sam3 ;  in  particular,  Bishop  Patrick  and  Dr.  David  Jennings 
Of  modern  Scripture  critics  I  say  nothing;  for  prejudice,  justly 
or  unjustly,  may  lie  against  them.  Not  that  the  question  is  to  be 
settled  by  human  authority.  Our  only  appeal  for  decision  is  to 
the  Bible  itself,  fairly  interpreted.  But  the  mention  of  venera- 
ble names  may  be  useful  to  allay  the  apprehensions  of  some 
good  persons,  who  only  hear  obscurely  of  these  subjects,  and 
have  not  the  means  of  forming  an  independent  judgment  on  solid 
grounds. 

*'  I  therefore,  with  many,  feel  greatly  obliged  to  Dr.  Buckland 
for  having  come  in  aid  of  this,  which  I  believe  to  be  tlie  true  sense 
and  meaning  of  the  sacred  writers.    I  am  framing  no  hypotheses 
in  geology  ;  I  only  plead  that  tlie,  ground  is  clear,  and  that  the 
dictates  of  Scripture  interpose  no  bar  to  observations  and  reason- 
ings upon  the  mineralogical  constitution  of  the  earth,  and  the  re- 
mains of  organized  creatures  which  its  strata  disclose.     If  those 
investigations  should  lead  us  to  attribute  to  the  earth,  and  to  the 
other  planetary  and  astral  spheres,  an  antiquity  which  millions 
or  ten  thousand  millions  of  years  might  fail  to  represent,  tlie  di- 
vine records  forbid  not  their  deduction.     Let  but  the  geologist 
maintain  what  his  science  so  loudly  proclaims,  that  the  universe 
around  us  has  been  formed,  at  whatever  epoch,  or  through  what 
ever  succession  of  epochs,  to  us  unknown,  by  the  power  and  wis 
dom  of  an  Almighty  First  Cause ;  let  him  but  reject  the  absurd 
ities  of  pre-existent  matter,  of  an  eternal  succession  of  finite  be 
ings,  of  formations  without  a  former,  laws  without  a  lawgiver,  ana 
nature  without  a  God ;  let  him  but  admit  that  man  is  but  of  yes 
terday,  and  that  the  design  of  revelation  is  to  train  him  to  the  no- 
blest purity  and  happiness  in  the  immortal  enjoyment  of  his  Cre- 
ator's beneficence,  and  he  will  find  the  doctrines  of  the  Bible  not 
an  impediment,  but  his  aid  and  his  joy." — Dr,  J.  Pye  Smith. 


CONNECTION  OF  GEOLOGY  WITH  REVELATION.     345 

"  Many  of  the  early  fathers  of  the  Church  were  very  explicit 
on  this  subject.  Augustin,  Theodoret,  and  others,  supposed  that 
the  first  verse  of  Genesis  describes  the  creation  of  matter  distinct 
from,  and  prior  to,  the  work  of  six  days.  Justin  Martyr  and 
Gregory  Nazianzen  believed  in  an  indefinite  period  between 
the  creation  of  matter  and  the  subsequent  arrangement  of  all 
things.  Still  more  explicit  are  Basil,  Caesarius,  and  Origen.  It 
would  be  easy  to  quote  similar  opinions  from  more  modern  writ^ 
ers,  who  lived  previous  to  the  developments  of  geology." — Pres- 
ident HitcJicock. 

"  The  interval  between  the  production  of  the  matter  of  the 
chaos  and  the  formation  of  light  is  undescribed  and  unknown." 
— Bishop  Horsley. 

"  By  the  phrase  in  the  beginning ,  the  time  is  declared  when 
something  began  to  be.  But  when  God  produced  this  remark- 
able work,  Moses  does  not  precisely  define." — Doederlin. 

"  The  detailed  history  of  creation  in  the  first  chapter  of  Gen- 
esis begins  at  the  middle  of  the  second  verse." — Dr.  Chalmers. 

"  Our  best  expositors  of  Scripture  seem  to  be  now  pretty  gen- 
erally agreed  that  the  opening  verse  in  Genesis  has  no  necessary 
connection  with  the  verses  which  follow." — Dr.  Daniel  King. 

"  That  a  very  long  period — how  long,  no  being  but  God  can 
tell — intervened  between  the  creation  of  the  world  and  the  com- 
mencement of  the  six  days'  work  recorded  in  the  following  verses 
of  the  first  chapter  of  Genesis,  there  can,  I  think,  be  no  reason- 
able doubt."— Dr.  Pond. 

II.  A  second  apparent  discrepancy  between  geology  and  revela- 
tion relates  to  the  time  of  the  introduction  of  death  and  the  reasons 
therefor. 

Several  passages  of  the  sacred  record  teach  us  that  the  death 
of  man  was  a  penal  infliction  consequent  upon  the  sin  of  our 
first  parents. 

"  By  one  man  sin  entered  into  the  world,  and  death  by  sin, 
and  so  death  has  passea  upon  all  men,  for  that  all  have  sinned." 

What  does  the  Bible  teach  in  respect  to  the  death  of  man  ? 
P2 


346     CONNECTION  OF  GEOLOGY  WITH  REVELATION. 

Other  passages  appear  to  teach  the  same  doctrine,  that  death 
and  the  pain  which  attends  it  were  the  result  of  sin. 

The  only  question  is,  whether  this  penalty  relates  also  to  the 
brute  animals ;  that  is,  whether  death  came  into  the  system  of 
organization  through  the  apostacy  of  man  1 

There  are  no  passages  in  the  Bible  which  assert  or  imply  that 
death  to  the  inferior  races  was  immediately  connected  with  tho 
fall  of  Adam. 

It  would  be  certainly  contrary  to  natural  justice  to  punish  an 
imals  generally  for  the  fault  of  one  particular  species.  Neither 
reason  nor  revelation  teach  or  demand  this ;  and  yet  it  is  a  very 
common  opinion.  It  has  been  suggested  by  an  able  writer  or. 
this  subject  that  the  idea  was  derived  from  Milton's  Paradise 
Lost  rather  than  from  the  Bible. 

"  She  pluck'd,  she  ate ! 

Earth  felt  the  wound,  and  Nature,  from  her  seat, 
Sighing  through  all  her  works,  gave  signs  of  woe 
That  all  was  lost." 

"The  sun      . 

Had  first  his  precept  so  to  move,  so  shine, 
As  might  affect  the  earth  with  cold  and  heat 
Scarce  tolerable,  and  from  the  north  to  call 
Decrepit  winter ;  from  the  south  to  bring 
Solstitial  summer's  heat." 

"  Some  say  he  bid  his  angels  turn  askance 
The  poles  of  earth  twice  ten  degrees  and  more 
From  the  sun's  axle ;  they  with  labor  push'd 
Oblique  the  centric  globe." 

"  Thus  began 

Outrage  from  lifeless  things ;  but  discord  first, 
Daughter  of  Sin,  among  the  irrational 
Death  introduced,  through  fierce  antipathy 
Beast  now  with  beast  'gan  war,  and  fowl  with  fowl, 
And  fish  with  fish :  to  graze  the  herb  all  leaving, 
Devour'd  each  other." 

Does  the  Bible  teach  the  same  in  respect  to  the  brute  animals  ?  From  what 
source  have  ideas  on  this  subject  been  obtained  ? 


0^  CONNECTION  OF  GEOLOGY  WITH  REVELATION.     347 

This  description  seems  to  have  been  incorporated  into  the 
Christian  system  as  of  divine  authcrity.  It  accords  with  the  sen- 
timent of  the  pious  heart  to  attribute  the  disorders  of  earth  and 
death  itself  to  sin.  But  we  ought  to  be  careful,  and  not  substitute 
the  imaginations  of  the  poet  for  the  truths  of  revelation. 

Assuming  that  the  death  of  the  human  species  was  the  penalty 
of  transgression,  we  have  the  most  positive  proof  that  it  occurred 
to  the  inferior  animals  in  millions  of  cases  before  man  was  crea- 
ted. The  remains  of  animals  extend  below  those  of  men  in  the 
rocks  to  a  depth  of  at  least  six  miles,  and  this  fact  shows  that 
death  was  introduced  long  before  sin  existed  in  this  world. 

1.  But  perhaps  the  most  convincing  argument  on  this  subject 
is  derived  from  the  structure  and  habits  of  the  carnivorous  races. 
Their  teeth  and  whole  organization  render  it  impossible  for  them 
to  exist  on  vegetable  food.     They  were  intended  to  devour  flesh, 
and  this  implies  the  necessity  of  the  death  of  some  to  sustain 
others.     The  same  organization  is  found  in  those  animals  whose 
remains  are  found  in  the  rocks,  and,  in  some  cases,  one  animal 
is  found  in  the  body  of  another,  both  changed  to  stone,  an  ever- 
during  monument  that  death  was  a  law  of  nature  long  before  man 
existed. 

2.  Death  also  results  from  organization  itself;  the  parts  wear 
out  and  decay,  and  were  evidently  never  intended  for  terrestrial 
immortality.     In  fact,  we  can  see  much  good  resulting  from  death 
to  the  inferior  races ;  for,  as  their  powers  decay,  they  give  place 
to  new  and  more  vigorous  forms  of  life,  so  that  the  aggregate  of 
enjoyment  is  much  greater  than  it  could  be  under  any  other  sys- 
tem ;  there  is,  moreover,  a  necessity  either  to  restrain  the  multi- 
plication of  individuals,  or  to  remove  some  of  the  species  to  pre- 
vent the  world  from  being  so  filled  that  their  support  would  be 
impossible. 

"Put  the  case,"  says  Dr.  J.  Pye  Smith,  "  that  there  be  no  death. 
Upon  this  supposition,  two  or  three  modes  are  conceivable : 

What  proof  that  death  to  the  inferior  animals  did  not  result  from  the  sin  of 
Adam  ?  What  is  the  most  convincing  argument  on  this  subject  ?  From  what 
does  death  necessarily  result  1 


348     CONNECTION  OF  GEOLOGY  WITH  REVELATION.  • 

"  a.  Life  prolonged  without  food.  But  this  would  be  irrecon- 
cilable with  a  system  of  successive  production,  nutrition,  assimi- 
lation, and  growth.  Such  beings  would  be  perpetual  possessors 
of  the  earth  and  the  waters,  in  their  own  persons,  without  any 
progeny.  Only  imagine  such  a  world !  Shall  we  say  one,  01 
some  number  of  each  species  1  Quadruped,  bird,  reptile,  fish, 
mollusc,  zoophyte,  insect  of  every  kind,  including  all  those  in- 
visible without  microscopic  aid  :  each  immortal. 

"  b.  Life  prolonged  by  vegetable  food  alone.  But  this  would 
require  a  differently  constituted  vegetable  world  ;  for  there  is  no 
plant  on  the  land  or  in  the  sea  which  does  not  nourish  myriads 
of  minute  insects,  which  are  destroyed  in  the  eating  of  the  plants. 

"c.  Must  there  be  any  multiplication  by  progeny  upon  any 
scheme?  Then,  either  the  whole  number  must  be  extremely 
small ;  or  be  kept  down  in  some  inconceivable  way ;  or  would, 
after  a  time,  multiply  to  that  degree  that  there  would  not  be  room 
for  them.  The  land  and  the  waters  would  be  over-filled !" 

3.  It  is  not  improbable  that  our  first  parents  had  witnessed  the 
death  of  the  inferior  animals  before  their  transgression.  It  would 
seem  that  they  must  have  understood  the  nature  of  the  threaten- 
ing :  "  In  the  day  thou  eatest  thereof  thou  shalt  surely  die/'  or, 
if  they  had  not  this  experience,  still  it  is  true  that  millions  of 
animalcules  which  exist  in  water  and  vegetables  must  have  been 
destroyed  in  the  food  of  man  and  other  animals  previous  to  sin. 

Some  have  supposed  that  the  whole  organization  was  changed 
after  the  fall ;  that,  previous  to  that  event,  all  animals  were  sup 
ported  upon  vegetable  food ;  but  the  above  fact  is  fatal  to  such  an 
hypothesis ;  and,  if  it  were  not,  it  is  too  extravagant  to  be  received ; 
the  inhabitants  of  the  ocean,  as  whales  for  example,  would  have 
found  it  rather  inconvenient  to  have  obtained  a  sufficient  amount 
of  vegetable  food,  even  if  they  could  have  subsisted  upon  it. 

Death  is  a  necessary  law,  both  of  the  animal  and  vegetable 
kingdoms,  and,  unless  the  whole  system  were  changed,  it  would 

What  would  be  the  condition  of  the  world  if  death  had  not  been  introduced  ? 
Did  our  first  parents  probably  witness  the  death  of  the  inferior  animal*  * 
What  hypothesis  has  been  suggested  ?  What  objections  to  it  ? 


CONNECTION  OK  GEOLOGY  WITH  REVELATION.     349 

be  impossible  to  avoid  it.  It  is,  moreover,  certain  that  no  change 
of  the  kind  has  taken  place  since  the  first  animals  were  brought 
upon  the  surface  of  our  planet,  and  their  bodies  entombed  in 
the  lowest  fossiliferous  rocks.  Carnivorous  races  have  existed 
during  all  the  geological  periods. 

Why,  then,  it  may  be  asked,  is  it  necessary  to  suppose  that  the 
death  of  mankind  is  an  exception  to  this  general  law  1  what  force 
is  there  in  the  threatening  as  a  penalty  for  sin  1  and  in  what  sense 
can  it  be  said  that  "  by  one  man  came  sin,  and  death  by  sin  ?" 
The  true  answer  to  these  inquiries  is,  that  if  man  had  not  sinned, 
he  would  not  have  been  subject  to  death,  but  would  have  been  trans 
lated  at  the  end  of  his  probation,  without  experiencing  the  change 
in  the  same  way  with  the  inferior  animals  ;  but  because  he  sinned, 
he  was  doomed  to  suffer  the  pains  of  death,  even  as  the  beasts  that 
perish.  To  him  it  is  a  much  greater  calamity,  for  he  has  intel- 
ligence, and  can  anticipate  it.  The  sting  of  death  is  sin  ;  he  is, 
therefore,  all  his  lifetime  subject  to  bondage  through  fear  of  death. 
This  theory  relieves  us  from  all  difficulty  in  respect  to  the  intro- 
duction of  death  previous  to  sin,  and  renders  the  truths  of  science 
and  of  revelation  perfectly  consistent  with  each  other. 

In  order  to  account  for  the  introduction  of  death  previous  to 
sin,  another  view  is  presented  by  some  writers. 

To  the  divine  mind,  all  the  events  which  would  transpire 
throughout  the  universe  were  present  before  the  work  of  crea- 
tion commenced.  This  is  a  result  of  his  foreknowledge;  sin 
was,  of  course,  included  in  this  knowledge,  and  God  arranged 
all  things  in  view  of  that  event.  He  made  a  world  adapted  to  a 
fallen  race,  and  introduced  death  as  a  part  of  the  system,  because 
sin  was  included  in  it.  In  this  view  death  may  be  said  to  be  the 
penalty  for  sin,  and  this  theory  may  be  more  satisfactory  to  some 
minds  than  the  one  given  above. 

If.  however,  the  views  now  presented  do  not  prove  that  the 
facts  of  science  are  consistent  with  revelation,  it  would  still  be 
unreasonable  tc  believe  that  either  record  was  false,  for  other 

What  other  theory  to  account  for  the  introduction  of  death  as  a  consequence 
of  sin  ? 


350     CONNECTION  OF  GEOLOGY  WITH  REVELATION. 

modes  of  interpretation  may  yet  be  suggested,  and  future  discov 
cries  may  be  made,  so  that  both  shall  be  seen  to  proceed  from  the 
same  source  of  light  and  truth. 

Astronomy  was  for  a  long  time  supposed  to  be  hostile  to  rev 
elati?n,  but  all  the  difficulties  which  it  presented  have  vanished 
as  the  word  and  tne  works  of  God  have  been  better  understood. 

Ancient  monuments  and  inscriptions  have  also  been  referred 
tc  as  conflicting  with  the  truth  of  the  sacred  record,  but  these 
too,  have  all  yielded  a  willing  testimony  to  its  truth.  In  fine,  the 
word  of  God  has  been  assailed  from  every  department  of  human 
knowledge,  and  has  come  out  of  the  contest  not  only  victorious, 
but  has  gathered  new  strength  by  every  such  conflict ;  so  that 
the  Christian  believer  may  never  fear  that  science  and  revelation 
will  come  into  such  deadly  hostility  that  a  reconciliation  will  not 
be  effected. 

They  are  but  parts  of  one  great  system,  united  by  mutual  affini 
ties.  They  are  divergent  streams,  flowing  from  the  same  fount- 
ain, each  sending  forth  its  fertilizing  influences  to  renovate  and 
bless  the  world.  Their  circling  currents  mingle  in  the  same  great 
ocean ;  and  while  the  philosopher  lifts  up  his  eyes  to  heaven  with 
the  devout  exclamation,  "  Great  and  marvelous  are  thy  works, 
Lord  God  Almighty!  in  wisdom  hast  thou  made  them  all,"  the 
Christian  may  respond  with  deeper  gratitude  and  in  loftier  strains, 
"  Thou  hast  magnified  thy  word  above  all  tliy  works  ;"  and  both 
may  unite  in  exploring  those  higher  mysteries  which  pertain  to 
the  spiritual  kingdom  of  God. 

What  other  sciences  have  been  supposed  to  be  hostile  to  revelation  ?     What 
has  been  the  resnt? 


INDEX. 


Atrita  ....................   86 

Adige  River  .................. 

JEtna,  Mount  ................. 

Aluminium  ................... 

Alum  Shales  .................. 

Amazon  River  ................ 

Ammomtidae  .................. 

Ammonites  ................... 

Amygdaloid  ........  .  ......... 

Animalcules  .................. 

Animal  Kingdom  .............. 

Annelidans  ................... 

Anoplotherium-  ................ 

Antiquity  of  the  Earth  ......... 

Apteryx  Australis  ............. 

Aqueous  Agencies..  ........... 

Arachnida  ____  .  ___  .  ........... 

Artesian  Wells  ................ 

Articulate  ................  .... 

Artificial  Excavations  .......... 

Atmospheric  Agencies  ......... 

Augite  ....................... 

Auvergne  .................... 


Page 

104 

25 

52 

7 

235 

22 

219 

219 

296 

79 

82 

103 

205 

306 

93 

16 

103 

116 

102 

115 

17 

11 

193 


Barrier  Reefs 79 

Basalt 295 

Basaltic  Columns 298 

Basilosaurus 202 

Basin-shaped  Deposits 47 

of  Garonne 178 

of  Vienna 179 

of  Thames 190 

• of  Hampshire 191 

of  Auvergne 193 

Belemnites 218,  232 

Benevolence  of  God 332 

Birds 184 

Blue  Marls 175 

Bowlders 127 

Bradford  Clay 229 

Brontozoum 248 

Brown  Coal  Formation 169 

Buhr-stone  Group 187 

Burrampooter 21 

Calamites 259 

Calcaire  Grossier 192 


Calcaire  Siliceux 192 

Calcareous  Grits 228 

Calcium 7 

Cambrian  Series 283 

Carbon 8 

Carboniferous  System 256 

Carcharodon 184 

Cephalaspis 273 

Ch<eroptamus 205 

Chalk 212 

Marl...                                .  212 


Cheirotherium 246 

Chemical     Constitution     of    the 

Earth 1 

Chlorine 9 

Chlorite 12 

Cirrhopods 103 

Clathraria 224 

Clay  Slates 288 

Cliffs  of  Cayuga  Lake 44 

of  York  River 174 

of  James  River 174 

Coal,  Origin  of 264 

Columnar  Structure 296 

Coprolites 200 

Coral  Rag 228 

Reefs 76 

,  Extent  of 77 

,  Increase  of 78 


Corals 75 

Coralline  Crag 177 

Corn-brash 229 

Cretaceous  System 211 

Crustaceans 103 

Crystalline  Marble 288 

Ctenoid 200 

Cumbrian  Series 283 

Cycadea? 231 

Cycloid 200 

Cypris 317 

Degradation 46 

Deluge 323 

Devonian  System 270 

Dinotheriuin 185 

Dirt  Bed 227 

Disintegration 17 

Drift 123 


362 


INDEX, 


Drift,  Limits  of.... 

,  Transport  of . 

,  Direction  of  . 

,  Age  of 

,  Unaltered 

,  Altered 


Earthquake  of  Lisbon 

Earthquakes 

,  Motion  of 

,  Effects  of 

Elephas  Primogeuius 

Endogeuites 

Eocene  of  the  United  States 

of  James  River 

of  Ashley   and    Cooper 

Rivers 

Eocene  of  Europe 

Basins  of  Auvergne 

Excavations  by  Water 

Feldspar 

Feldspathic  Granite 

Fingal's  Cave . 

Fluorine 

Footmarks 

Foraminifera 

Forest  Marble 

Fossil  Figs 

Fossilization 

Fossils  of  the  Trias 

,  Pleistocene 

of  Pliocene 

•  of  Miocene 

of  Eocene 

of  Cretaceous  System  ... 

—  of  Wealden 

of  Oolite 

of  Lias 

•  of  Trias 

of  Permean  System 

of  Devonian  System 

of  Carboniferous  System. 

of  Silurian  System 

Fracture  of  Slate  Hills  , 

Fringing  Reefs 

Frost 

Fuller's  Earth 


Ganoid 

Gault 

Gay  head 

Geological  History 

Agencies,  Intensity  of 


Page 

124 
124 
125 
135 
123 
142 

60 

60 

61  ! 

62 

157 

224 

187 

188 

188 
189 
193 
116 

10 

292 

297 

9 

246 
197 
229 
196 
101 
243 
148 
170 
181 
195 
215 
224 
231 
236 
243 
254 
271 
256 
275 
140 
76 
18 
230 

21 

200 

213 

173 

4 

15 


Page 

Geological  Agencies,  classification 

of 15 

Geology,  Definition  of 1 

Giant's  Causeway 296 

G  acial  Furrows 129 

Glaciers 29 

,  Origin  of 29 

,  Motion  of 30 

-,  Effects  of 33 


Glen  Roy 1 47 

Gneiss 289 

Goniopholis 225 

Graham's  Island 65 

Granite 291 

Granitic  Rocks 291 

Graphic  Granite 292 

Great  Geyser 62 

Limestone  Formation 167 

Oolite 229 

Green  Sand 213 

Greenstone 295 

Gypsum 12 

Hastings  Sand 222 

Heterocercal 200 

History  of  each  Period 114 

Holoptychus 268,  273 

Homocercal 200 

Hornblende 11 

Slate  . .  .289 


Hydrogen 8 

Hylaeosaurus 225 

Hyracotherium 205 

Icebergs 36 

,  Origin  of 36 

,  Motion  of 38 

,  Dissolution  of 40 

.Effects  of 40 

Ichthyodorulites 239 

Ichthyosaurus 239 

Igneous  Agencies 49 

Iguanodon 225 

Indusial  Limestones 195 

Inferior  Oolite 230 

Infusorial  Animals 181 

Iron 8 

Joints 287 

Jurassic  System 230 

Kilauea 54 

,  Eruptions  of 56 


Kimmeridge  Clay 228 


INDEX. 


353 


Page 

Landslides 28 

Lava 299 

,  Characters  of 59 

Leiodon 221 

LeithaKalk 279 

Lepidodendron ...  261 

Lepidostrobus 262 

Liassic  System 235 

Lignite 198 

Lily  Encrinite 243 

Limestone " 11 

London  Clay „...  190 

Longevity  of  Species 90 

Lower  Lias 236 

Manganese 9 

Marine  Agencies 35 

Formation 47 

Terraces 147 

Mastodon 150 

Means  of  Observation 115 

Megalichthys 268 

Megalosaurus 233 

Megatherium 154 

Mesozoic 210 

Metamorphic  Strata 285 

Metamorphism 286 

Mica 11 

Slate 289 

Middle  Lias 236 

Millstones 188 

Miocene 172 

of  United  States 172 

of  Europe 177 

Alluvium 180 

of  Auvergne 180 

Mississippi  River 22 

Molasse 178 

Mollusca 84, 104 

Mososaurus 221 

Myliobatis 201 

Mylodon 153 

Myriapods 103 

Nautilidse 219 

Nebular  Hypothesis 304 

Nematoneura 84,104 

Nerinsean  Limestone 231 

-New  York  System 275 

Niagara  Falls 19 

Nipadites 196 

Nitrogen 9 

Noachian  Deluge 323 

Norwich  Crag 167 

fvammnlites  ..  .197 


Page 

Nummulitic  Formation 195 

Obsiiium 300 

Oceanic  Currents 45 

(Esars 144 

Old  Red  Sandstone 270 

Oolite 194,226 

of  United  States 226 

of  Europe 227 

Ornithopus 248 

Organic  Agencies 75 

Bodies 105 

Durability  of 101 

Remains 98 

Otozoum 251 

Oxford  Clay 228 

Oxygen -  7 

Palaeoniscus 256 

Palaeontology 82 

Palreotherium 204 

Paleozoic  Periods 253 

Rocks  ..  .    118 


Palisades 298 

Paper  Coal 169 

Paris  Basin 191 

Pentacrinites 237 

Permean  System  .„ 254 

Petrifaction 108 

Phascolotherium 235 

Phocodon 186 

Phosphorus 9 

Pitch  Stone 300 

Placoid 199 

Plants 80 

,  Distribution  of 94 


Plastic  Clay 191 

Platysomus 256 

Pleistocene 141 

,  Climate  of 163 

,Ageof 158 

,  Geography  of 160 


Plesiosaurus 240 

Pliocene 166 

Plirfsaurus 233 

Polemarchus,.. 248 

Polishing  Slate 182 

Polypes 75 

Porcelain  Clay 292 

Porphyritic  Granite 292 

Porphyry 295 

Portland  Beds 223 

Sand 228 

Potassium 8 

Power  of  God 33€ 


534 


INDEX. 


Page 

Lagoon  Reefs 77 

Lakes,  Bursting  of 26 

Primary  Strata 118,  285 

Pterichthys 273 

Pterodactyl 234 

Pulpit  Rock 43 

Pumice 60,300 

Purbeck  Strata 223 

Quartz 10 

Rock 293 

Quaternary 123 

Rain T 17 

Rana  Diluviana 172 

Rivers 19 

Salt  Lakes 27 

Santee  Beds 188 

Sauropus '...  268 

Saw-fish... t 201 

Scoria 300 

Secondary  Periods 209 

Serpentine 12 

Shark's  Teeth 183,  199,  200 

Shells 80 

Sigillaria 262 

Skaptar  Jokul 54 

Silicious  Sinter 28 

Silicon 7 

Silurian  System 275 

Siphuncle 219 

Sivatherium 205 

Slaty  Cleavage 287 

Sodium 8 

Species 86 

,  Origin  of 87 

,  Nature  of 89 

,  Duration  of 90 

,  Extinction  of. 92 

Springs 27 

Stalactites 27 

S  falagni  ite 27 

Steropezoum  Ingens 248 

Stigmaria 262 

Strata,  Inclination  of 117 

Stratified  Rocks 12,  111 

Streams  of  Stones. 133,  135 

Stria3 ' 127 

Sub-Apennine  Tertiary 169 

Submarine  Earthquakes 65 

Suchosaurus 225 

Sulphur 8 

Syenite 292 

THE 


Talc 12 

Talus 18 

Tentaculites  Ornatus 279 

Terebratuke 218 

Tertiary  Period 164 

Terraces 320 

Thenaropus  Heterodactylus 268 

Theory  of  Drift 137 

of  Geysers 66 

of  Internal  Heat 70 

of  Transmutation 87 

of  Volcanoes 66 

Thermal  Springs 62 

Tomboro 58 

Trachyte 295 

Transition  Rocks 118 

Trappean  Rocks 295 

Trap  Tuff 300 

Tretostemon 226 

Triassic  System 241 

Tufaceous  Breccia 300 

Unity  of  God 332 

Unstratified  Rocks 12,  290 

Uplifts 106 

Upper  Lias 235 

Val  di  Noto 167 

Valley  of  Switzerland 178 

Vertebrata 83 

Vesuvius 51 

Volcanic  Breccia 300 

Islands 64 

Rocks 299 

Trap 300 

Volcanoes 50 

,  Active 49 

,  Eruptions  of 50 

,  Extinct 49,  300 

,  Static  Pressure  in  ...  59 

Waves 41 

.Effects  of 41 

,  Motion  of 41 

,  Sizeof 41 


Weald  Clay 222 

Wealden 224 

Formation ...  ...   222 


Whale 151 

Wisdom  of  God 331 

Xauthidium 215 

Yellow  Marls 176 

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guage, together  with  appropriate  Exercises  in  the  translating  and  writing 
of  Greek.  For  the  use  of  Beginners.  12rno,  Sheep  extra,  75  cents. 

Anthon's  Greek  Composition. 

Greek  Lessons,  Part  II.  An  Introduction  to  Greek  Prose  Composition,  with 
a  Complete  Course  of  Exercises  illustrative  of  all  the  important  Principles 
of  Greek  Syntax.  12mo,  Sheep  extra,  75  cents. 

Anthon's  Greek  Grammar. 

For  the  use  of  Schools  and  Colleges.     12mo,  Sheep  extra,  75  cents. 

Anthon's  New  Greek  Grammar. 

From  the  German  of  Kiihner,  Matthiae,  Buttmann,  Rost,  and  Thiersch ;  to 
which  are  appended  Remarks  on  the  Pronunciation  of  the  Greek  Language, 
and  Chronological  Tables  explanatory  of  the  same.  12mo,  Sheep  extra,  75 
cents. 

Anthon's  Greek  Prosody  and  Metre. 

For  the  use  of  Schools  and  Colleges ;  together  with  the  Choral  Scanning  of 
the  Prometheus  Vinctus  of  JEscliylus,  and  CEdipus  Tyrannus  of  Sophocles. 
To  which  are  appended  Remarks  on  the  Indo-Germanic  Analogies.  12mo, 
Sheep  extra,  75  cents. 

Anthon's  Jacobs's  Greek  Reader. 

A  Greek  Reader,  principally  from  the  German  Work  of  Frederic  Jacobs. 
With  English  Notes,  Critical  and  Explanatory,  a  Metrical  Index  to  Homer 
and  Anacreon,  and  a  copious  Lexicon.  12mo,  Sheep  extra,  $1  00. 

Anthon's  Xenophon's  Anabasis. 

With  English  Notes,  Critical  and  Explanatory,  a  Map  arranged  according  to 
the  latest  and  best  Authorities,  and  a  Plan  of  the  Battle  of  Cunaxa.  12mo, 
Sheep  extra,  $1  25. 

Anthon's  Xenophon's  Memorabilia  of  Socrates. 

With  English  Notes,  Critical  and  Explanatory,  the  Prolegomena  of  Kiihner, 
Wiggers's  Life  of  Socrates,  &c.,  &c.  Corrected  and  enlarged.  12mo,  Sheep 
extra,  $1  00. 

Anthon's  Homer. 

The  First  Six  Books  of  Homer's  Iliad.  To  which  are  appended  English 
Notes,  Critical  and  Explanatory,  a  Metrical  Index,  and  Homeric  Glossary. 
New  and  enlarged  Edition.  Portrait.  12mo,  Sheep  extra,  $1  25. 

Anthon's  Manual  of  Greek  Antiquities. 

From  the  best  and  most  recent  Sources.  Numerous  Illustrations.  12mo, 
Sheep  extra,  8S  cents. 


Harper  fy  Brothers'  School  and  College  Text-Books.      5 
Anthon's  Manual  of  Roman  Antiquities. 

From  the  most  recent  German  Works.  With  a  description  of  the  City  of 
Rome,  &c.  Numerous  Illustrations.  12mo,  Sheep  extra,  88  cents. 

Anthon's  Manual  of  Greek  Literature. 

From  the  earliest  authentic  Periods  to  the  close  of  the  Byzantine  Era.  With 
a  Critical  History  of  the  Greek  Language.  12mo,  Sheep  extra,  $1  00. 

Anthon's  Smith's  Dictionary  of  Antiquities. 

A  Dictionary  of  Greek  and  Roman  Antiquities,  from  the  best  Authorities, 
and  embodying  all  the  recent  Discoveries  of  the  most  eminent  German 
Philologists  and  Jurists.  First  American  Edition,  corrected  and  enlarged, 
and  containing  also  numerous  Articles  relative  to  the  Botany,  Mineralogy, 
and  Zoology  of  the  Ancients.  By  CHABLES  ANTHON,  LL.D.  Royal  8vo, 
Sheep  extra,  $4  00. 

Anthon's  Smith's  Antiquities.     Abridged, 

By  the  Authors.     12mo,  Half  Sheep,  90  cents. 

Anthon's  Classical  Dictionary. 

Containing  an  Account  of  the  principal  Proper  Names  mentioned  in  Ancient 
Authors,  and  intended  to  elucidate  all  the  important  Points  connected  with 
the  Geography,  History,  Biography,  Mythology,  and  Fine  Arts  of  the  Greeks 
and  Romans,  together  with  an  Account  of  the  Coins,  Weights,  and  Meas- 
ures of  the  Ancients,  with  Tabular  Values  of  the  same.  Royal  8vo,  Sheep 
extra,  $4  00. 

Anthon's  Smith's  New  Classical  Dictionary 

Of  Greek  and  Roman  Biography,  Mythology,  and  Geography.  Numerous 
Corrections  and  Additions.  Edited  by  CHAELES  ANTHON,  LL.D.  Royal 
8vo,  Sheep  extra,  $2  50. 

Anthon's  Lat.-Bng.  and  Eng.-Latin  Dictionary. 

A  Latin-English  and  English-Latin  Dictionary,  for  the  use  of  Schools. 
Chiefly  from  the  Lexicons  of  Freund,  Georges,  and  Kaltschmidt.  SinaU 
4to,  Sheep,  $2  00. 

Anthon's  Riddle  and  Arnold's  English-Latin  Lexicon. 

Founded  on  the  German-Latin  Dictionary  of  Dr.  C.  E.  GEOBGES.  FirsS 
American  Edition,  carefully  revised,  and  containing  a  copious  Dictionary  of 
Proper  Names  from  the  best  Sources.  By  CIIAELES  ANTHON,  LL.D.  Royal 
Svo,  Sheep  extra,  $3  00. 

Anthon's  Ancient  and  Mediaeval  Geography. 

For  the  use  of  Schools  and  Colleges.    Svo,  Muslin,  $1 50  ;  Sheep  extra,  $1  75. 

Barton's  Grammar. 

An  Outline  of  the  General  Principles  of  Grammar.  With  a  Brief  Exposi- 
tion of  the  Chief  Idiomatic  Peculiarities  of  the  English  Language.  To 
which  Questions  have  been  added.  Edited  and  Enlarged  by  the  Rev.  J. 
GBAEFF  BABTON,  A.M.,  Professor  of  the  English  Language  and  Literature 
in  the  New  York  Free  Academy.  IGmo,  Muslin,  38  cents. 


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